Hardeep Kumar

@nituk.ac.in

Assistant Professor, Physics
NIT Uttarakhand

Dr. Hardeep Kumar received his B.Sc. degree in Non-Medical from Himachal Pradesh University, Shimla in 2002 and M.Sc. degree in Physics from Guru Nanak Dev University Amritsar in 2004. He obtained Ph.D. degree in Physics from I.I.T. Delhi in 2011. His Ph.D. work is based on magnetic granular thin films. Dr. Hardeep worked as FAPESP Post-doctoral Fellow at University of Sao Paulo, Brazil from 09/2011 to 05/2014 and joined Amity University UP, Noida as Assistant Professor in 10/2014 and worked there for about 3 Year and 7 Months. He joined NIT Uttarakhand as Assistant Professor in 06/2018. Dr. Hardeep has co-supervised one Ph.D. scholar (07/2016-03/2021), and currently two Ph.D. students are working under his sole supervision in the area of Spintronics . He completed one research project (2016-19) sponsored by UGC-DAE CSR , Indore, and currently working on a project (2020-till date) sponsored by UGC-DAE CSR , Indore. His research interests are magnetic heterostructures for spintronics ap

EDUCATION

* Ph.D. (Physics) - Indian Institute of Technology Delhi, India - 2011
* M.Sc. (Physics) - GNDU Amritsar, India - 2004

RESEARCH INTERESTS

Magnetism, Thin films, Spintronics, Ion-irradiation, Hydrogen sensors

Scopus Publications

303

Scholar Citations

Scholar h-index

Scholar i10-index

Scopus Publications

Unraveling the structural and electronic features of tungsten nitride (WN<inf>x</inf>) thin films
Hardepinder Singh, Mukul Gupta, Parasmani Rajput, and Hardeep Kumar
Elsevier BV

Investigation of B2 phase formation by thermal annealing of Fe(Cu)/Rh multilayers
Preeti Negi, Mukul Gupta, Rajeev Rawat, Rajeev Joshi, V.R. Reddy, and Hardeep Kumar
Elsevier BV

Role of spin-glass-like interfaces in exchange-biased MnN/Fe thin films grown on W buffer layers
Hardepinder Singh, Mukul Gupta, Hind Prakash, Hardeep Kumar, and Himanshu Fulara
AIP Publishing
This study reports the growth and investigation of (001)-oriented MnN/Fe thin films on the W buffer layer, focusing on detailed exchange bias (EB) studies, including thermal evolution (300–10 K) and the training effect. At room temperature, the magnetically annealed α-W/MnN/Fe/Ta stack exhibits an EB field (HEB) of 118 Oe. With decreasing temperature, particularly below 100 K, both HEB and coercive field (HC) show substantial increases, with HEB displaying a more pronounced enhancement. Analysis of the temperature-dependent HEB and HC data reveals an exponential trend, indicative of a spin-glass-like interface in the MnN/Fe system. At 10 K, the pronounced EB is accompanied by an asymmetric “kinked” magnetization reversal, suggesting a transition from uniaxial to biaxial anisotropy below 50 K due to spin-glass-like magnetic frustration at the interdiffused MnN/Fe interface. Training effect measurements further support the spin-glass-like MnN/Fe interface, with two distinct training mechanisms observed at 10 K: “athermal” and “thermal.” Finally, the spin-glass model demonstrates an excellent fit for the training effect data, validating the presence of spin-glass-like disorder at the MnN/Fe interface.

Formation of B2-ordered FeRh alloy thin films on annealing of pure and nitrogen doped Fe/Rh multilayers
Preeti Negi, Mukul Gupta, Rajeev Rawat, Rajeev Joshi, Harsh Bhatt, Surendra Singh, V.R. Reddy, and Hardeep Kumar
Elsevier BV

Role of nitrogen partial pressure, deposition rate and annealing on stability of β-W phase
Hardepinder Singh, Mukul Gupta, Pooja Gupta, Rafaela F. S. Penacchio, Sergio L. Morelhao, and Hardeep Kumar
Springer Science and Business Media LLC

Structural and magnetic properties of FeRh films grown on MgO(0 0 1), MgO(0 1 1) and MgO(1 1 1) substrates
Hardeep Kumar, Sergio L. Morelhao, Gerson Pessotto, Hardepinder Singh, Anil K. Sinha, and Daniel R. Cornejo
Journal of Magnetism and Magnetic Materials Elsevier BV

Transformation of Au–Pd alloy nanoparticles to core-shell nanoparticles by electron irradiation
Deepti, Bhawini Tripathi, Hardeep Kumar, Ambuj Tripathi, Sunil Kumar, Saif Ahmad Khan, G.B.V.S. Lakshmi, Arka Bikash Dey, Gagan Sharma, Ajay Gupta,et al.
Elsevier BV

Improved hydrogen sensing behaviour in ion-irradiated Pd-Au alloy thin films
Deepti, Hardeep Kumar, Ambuj Tripathi, Arka Bikash Dey, Mukul Gupta, Richa Krishna, and D.K. Avasthi
Elsevier BV

Evidence of local structural influence on the shape driven magnetic anisotropy in electronically excited Ni nanoparticles embedded in SiO<inf>2</inf> matrix
Debalaya Sarker, Saswata Bhattacharya, H. Kumar, Pankaj Srivastava, and Santanu Ghosh
Springer Science and Business Media LLC
AbstractThe reliance of modern electronic era on ultrafast data recording has made the search for novel tools to tune nano-scale magnetic-anisotropy (MA) never-ending. We demonstrate a strong correlation between the spin-spin interactions, local atomic structure and the MA of Ni nanoparticles (NPs) embedded inside SiO2 matrix under swift heavy ion (SHI) irradiation. In contrast to traditional understandings, MA in Ni NPs along with their aspect ratio, first increases upto 5 × 1013 ions/cm2 SHI fluence (5e13) and gets reduced at highest fluence. Using angle dependent Extented-Xray-Absorption-Fine-Structure (EXAFS) and ab initio molecular dynamics (MD) simulations, we show that the anisotropy induced in local atomic structure upon irradiation is dependent on atomic spin-spin interactions, which gets reduced at highest fluence. The chosen model cluster (Ni38) used in our MD simulations is duly validated by comparing the pair-correlation-function of the structure with the EXAFS-Fourier-Transform. The lattice temperatures for the films irradiated at different fluences, as calculated from thermal-spike-model, are used for the respective MD runs. We conclude that the enhanced disorder in both the local atomic environment and spin alignment destroys the MA at the highest fluence in SHI irradiated Ni NPs. The findings therefore provide rich conceptual insights for designing magnetic devices using SHI-induced phenomena.

Strain effects on the magnetic order of epitaxial FeRh thin films
H. Kumar, D. R. Cornejo, S. L. Morelhao, S. Kycia, I. M. Montellano, N. R. Álvarez, G. Alejandro, and A. Butera
AIP Publishing
In this work, we report the experimental results obtained on a set of ∼90 nm thick FeRh epitaxial films deposited on MgO (001), MgO (111), and Al2O3 (0001) single crystal substrates. The magnetic characterization was achieved by measuring magnetization curves and ferromagnetic resonance as a function of temperature and orientation of the films with respect to the applied magnetic field. We discuss our results by comparing the characteristics of the antiferromagnetic-ferromagnetic transition among FeRh films of the same thickness but exposed to different post-growth annealings and deposited on substrates of different crystalline orientations. We have found that there is a correlation between the strain present in the films and their magnetic behavior, observing that a change in the in-plane stress from compressive to tensile tends to shift the magnetic transition by more than 60 K. The interplay between magnetic and elastic properties was further analyzed by ferromagnetic resonance, and we have found that the magnetoelastic component of the anisotropy varies from out-of-plane to in-plane, depending on the substrate. These findings could be of great importance if a precise tuning of the magnetic transition temperature or the magnetic anisotropy is needed for a specific application.In this work, we report the experimental results obtained on a set of ∼90 nm thick FeRh epitaxial films deposited on MgO (001), MgO (111), and Al2O3 (0001) single crystal substrates. The magnetic characterization was achieved by measuring magnetization curves and ferromagnetic resonance as a function of temperature and orientation of the films with respect to the applied magnetic field. We discuss our results by comparing the characteristics of the antiferromagnetic-ferromagnetic transition among FeRh films of the same thickness but exposed to different post-growth annealings and deposited on substrates of different crystalline orientations. We have found that there is a correlation between the strain present in the films and their magnetic behavior, observing that a change in the in-plane stress from compressive to tensile tends to shift the magnetic transition by more than 60 K. The interplay between magnetic and elastic properties was further analyzed by ferromagnetic resonance, and we have found that ...

Structural, morphological and magnetic characterization of electrodeposited Co-Fe-W alloys
R. Della Noce, A.V. Benedetti, M. Magnani, E.C. Passamani, H. Kumar, D.R. Cornejo, and C.A. Ospina
Elsevier BV

Enhancement in field emission current density of Ni nanoparticles embedded in thin silica matrix by swift heavy ion irradiation
Debalaya Sarker, H. Kumar, Rajkumar Patra, D. Kabiraj, D. K. Avasthi, Sarathlal K. Vayalil, S. V. Roth, P. Srivastava, and S. Ghosh
AIP Publishing
The field emission (FE) properties of nickel nanoparticles embedded in thin silica matrix irradiated with 100 MeV Au+7 ions at various fluences are studied here. A large increase in FE current density is observed in the irradiated films as compared to their as deposited counterpart. The dependence of FE properties on irradiation fluence is correlated with surface roughness, density of states of valence band and size distribution of nanoparticles as examined with atomic force microscope, X-ray photoelectron spectroscopy, and grazing incidence small angle x-ray scattering. A current density as high as 0.48 mA/cm2 at an applied field 15 V/μm has been found for the first time for planar field emitters in the film irradiated with fluence of 5.0 × 1013 ions/cm2. This significant enhancement in the current density is attributed to an optimized size distribution along with highest surface roughness of the same. This new member of field emission family meets most of the requirements of cold cathodes for vacuum mic...

Sub-Nanosecond Thermal Spike Induced Nanostructuring Of Thin Solid Films Under Swift Heavy Ion (SHI) Irradiation
S. Ghosh, H. Kumar, S. P. Singh, P. Srivastava, D. Kabiraj, D. K. Avasthi, D. Bürger, S. Zhou, A. Mücklich, H. Schmidt,et al.
Springer International Publishing

Influence of current density on crystalline structure and magnetic properties of electrodeposited Co-rich CoNiW alloys
A.M.P. Sakita, E.C. Passamani, H. Kumar, D.R. Cornejo, C.S. Fugivara, R.D. Noce, and A.V. Benedetti
Elsevier BV

Evidence of coexistence of ferromagnetic and antiferromagnetic phases in nearly equiatomic FeRh
Hardeep Kumar, Marcia C. A. Fantini, and Daniel R. Cornejo
Institute of Electrical and Electronics Engineers (IEEE)
Fe100-xRhx films were deposited on Si substrates with various Rh concentrations (conc.) (x) ~ 32 to 52% at. All the films showed the in-plane magnetic anisotropy due to the thin-film like structure i.e., shape anisotropy. For Rh conc. up to ~ 42% at., the films exhibit a single ferromagnetic (α') phase. However, for Rh conc. (x) > 42% at., there exists a mixture of ferromagnetic (α') and antiferromagnetic (α") phase. Nearly equiatomic samples ( x ~ 48 to 52% at.) showed abrupt enhancement in coercivity and a broad thermal hysteresis. This behavior is consistent with the presence of a mixture of FM and AFM phase. Thermal first-order-reversal-curves analysis showed that the AFM to FM phase transition is restricted to a region with FWHM of ~ T = 40 K, in spite of the mentioned broad thermal hysteresis.

Stabilization of feco alloy phase in feco-sio2 nanocomposites
Hardeep Kumar, L. Olivi;G. Aquilanti, S. Ghosh, P. Srivastava, D. Kabiraj, and D. K. Avasthi
International Association of Advanced Materials
A series of FeCo-SiO2 granular films of different FeCo atomic concentration (33-54%) have been prepared by fast atom beam sputtering technique and post-annealed in inert (Ar) and reducing (H2) gas environments. Fe and Co K-edge XANES analysis of as-deposited films indicate that both Fe and Co are present mainly in their elemental (Fe 0 , Co 0 ) state. A partial oxidation of Fe and Co is observed, as the FeCo alloy content decreases (54 to 33%) due to reduced particle size. XANES/XAFS analysis shows the formation of FeCo alloy with bcc Fe structure in H2 environment annealed films. The XRD and Raman analysis of Ar environment annealed films suggest the formation of Co3O4 and CoFe2O4 phases. The Ar environment is found not to be effective reducing medium to stabilize the FeCo alloy phase, while H2 environment annealing (450-700 o C) leads to formation of bcc FeCo alloy. Copyright © 2013 VBRI press.

Use of conventional electrochemical techniques to produce crystalline FeRh alloys induced by Ag seed layer
R.D. Noce, A.V. Benedetti, E.C. Passamani, H. Kumar, D.R. Cornejo, and M. Magnani
Elsevier BV

Role of Coulomb blockade and spin-flip scattering in tunneling magnetoresistance of FeCo-Si-O nanogranular films
Hardeep Kumar, Santanu Ghosh, Danilo Bürger, Lin Li, Shengqiang Zhou, Debdulal Kabiraj, Devesh Kumar Avasthi, Rainer Grötzschel, and Heidemarie Schmidt
AIP Publishing
In this work, we report the effect of FeCo atomic fraction (0.33 < x < 0.54) and temperature on the electrical, magnetic, and tunneling magnetoresistance (TMR) properties of FeCo-Si-O granular films prepared by atom beam sputtering technique. Glancing angle x-ray diffraction and TEM studies reveal that films are amorphous in nature. The dipole–dipole interactions (particle–matrix mixing) is evident from zero-field cooled and field-cooled magnetic susceptibility measurements and the presence of oxides (mainly Fe-related) is observed by x-ray photoelectron spectroscopy analysis. The presence of Fe-oxides is responsible for the observed reduction of saturation magnetization and rapid increase in coercivity below 50 K. TMR has been observed in a wide temperature range, and a maximum TMR of −4.25% at 300 K is observed for x = 0.39 at a maximum applied field of 60 kOe. The fast decay of maximum TMR at high temperatures and lower TMR values at 300 K when compared to PFeCo2/(1+PFeCo2), where PFeCo is the spin pol...

Ion beam-induced shaping of ni nanoparticles embedded in a silica matrix: From spherical to prolate shape
Hardeep Kumar, Santanu Ghosh, Devesh Kumar Avasthi, Debdulal Kabiraj, Arndt Mücklich, Shengqiang Zhou, Heidemarie Schmidt, and Jean-Paul Stoquert
Springer Science and Business Media LLC

Magnetic and field emission studies of atom beam sputtered Ni:SiO <inf>2</inf> granular films
Hardeep Kumar, Santanu Ghosh, D.K. Avasthi, D. Kabiraj, N.P. Lalla, T. Shripathi, and J.C. Pivin
Elsevier BV

Microstructure, electrical, magnetic, and extraordinary Hall effect studies in Ni: SiO<inf>2</inf> nanogranular films synthesized by atom beam sputtering
Hardeep Kumar, Santanu Ghosh, Danilo Bürger, Shengqiang Zhou, Debdulal Kabiraj, Devesh Kumar Avasthi, Rainer Grötzschel, and Heidemarie Schmidt
AIP Publishing
In this work we report on the synthesis of Ni:SiO2 nanogranular films with different metal fraction (0.10≤x≤0.68) and a homogeneous distribution of Ni particles by atom beam sputtering technique and on the study of their microstructure, electrical transport, magnetic properties, and on the observation of extraordinary Hall effect (EHE). Films with the Ni fraction x above percolation threshold (x≥0.58>xp) as revealed by resistivity versus temperature measurements have a large Ni particle size, pronounced ferromagnetic characteristics, and appreciable extraordinary Hall resistivity at 300 K. Furthermore, films above percolation have a relatively low, nearly temperature independent Ohmic resistivity smaller than 10−3 Ω cm and may be useful for Hall sensor applications. On the other hand, films below percolation threshold (x≤0.54 xp) show ferromagnetic characteristics with an enha...

Controlled reduction of size of Ag nanoparticles embedded in teflon matrix by MeV ion irradiation
Y.K. Mishra, V.S.K. Chakravadhanula, U. Schürmann, Hardeep Kumar, D. Kabiraj, S. Ghosh, V. Zaporojtchenko, D.K. Avasthi, and F. Faupel
Elsevier BV

Compositional analysis of atom beam co-sputtered metal-silica nanocomposites by Rutherford backscattering spectrometry
Hardeep Kumar, Y.K. Mishra, S. Mohapatra, D. Kabiraj, J.C. Pivin, S. Ghosh, and D.K. Avasthi
Elsevier BV

RECENT SCHOLAR PUBLICATIONS

Investigation of B2 phase formation by thermal annealing of Fe(Cu)/Rh multilayers
VRRHK P. Negi, M. Gupta, R. Rawat, R. Joshi
J. Mag. Mag. Mater. 613, 172671 (2025) 2024

Role of spin-glass-like interfaces in exchange-biased MnN/Fe thin films grown on W buffer layers
H Singh, M Gupta, H Prakash, H Kumar, H Fulara
Applied Physics Letters 125, 092404 2024

Formation of B2-ordered FeRh alloy thin films on annealing of pure and nitrogen doped Fe/Rh multilayers
HK Preeti Negi, Mukul Gupta, Rajeev Rawat, Rajeev Joshi, Harsh Bhatt ...
Journal of Magnetism and Magnetic Materials 581, 170941 2023

Role of nitrogen partial pressure, deposition rate and annealing on stability of β-W phase
SLMHK H. Singh, M. Gupta, P. Gupta, R. F. S. Penacchio
Applied Physics A 129 (312) 2023

Structural and magnetic properties of FeRh films grown on MgO(001), MgO(011) and MgO(111) substrates
DRC Hardeep Kumar, Sergio L. Morelhao, Gerson Pessotto, Hardepinder Singh ...
Journal of Magnetism and Magnetic Materials 556, 169442 2022

Transformation of Au–Pd alloy nanoparticles to core-shell nanoparticles by electron irradiation
B Tripathi, H Kumar, A Tripathi, S Kumar, SA Khan, G Lakshmi, AB Dey, ...
Journal of Alloys and Compounds 832, 154944 2020

Improved hydrogen sensing behaviour in ion-irradiated Pd-Au alloy thin films
H Kumar, A Tripathi, AB Dey, M Gupta, R Krishna, DK Avasthi
Sensors and Actuators B: Chemical 301, 127006 2019

Strain effects on the magnetic order of epitaxial FeRh thin films
H Kumar, DR Cornejo, SL Morelhao, S Kycia, IM Montellano, NR Alvarez, ...
Journal of Applied Physics 124 (8) 2018

Evidence of local structural influence on the shape driven magnetic anisotropy in electronically excited Ni nanoparticles embedded in SiO₂ matrix
D Sarker, S Bhattacharya, H Kumar, P Srivastava, S Ghosh
Scientific reports 8 (1), 1040 2018

Structural, morphological and magnetic characterization of electrodeposited Co–Fe–W alloys
R Della Noce, AV Benedetti, M Magnani, EC Passamani, H Kumar, ...
Journal of Alloys and Compounds 611, 243-248 2014

Enhancement in field emission current density of Ni nanoparticles embedded in thin silica matrix by swift heavy ion irradiation
D Sarker, H Kumar, R Patra, D Kabiraj, DK Avasthi, SK Vayalil, SV Roth, ...
Journal of Applied Physics 115 (17) 2014

Use of conventional electrochemical techniques to produce crystalline FeRh alloys induced by Ag seed layer
RD Noce, AV Benedetti, EC Passamani, H Kumar, DR Cornejo, ...
Journal of alloys and compounds 573, 37-42 2013

Influence of current density on crystalline structure and magnetic properties of electrodeposited Co-rich CoNiW alloys
AMP Sakita, EC Passamani, H Kumar, DR Cornejo, CS Fugivara, ...
Materials Chemistry and Physics 141 (1), 576-581 2013

Evidence of coexistence of ferromagnetic and antiferromagnetic phases in nearly equiatomic FeRh
H Kumar, MCA Fantini, DR Cornejo
IEEE transactions on magnetics 49 (8), 4506-4509 2013

Stabilization of FeCo alloy phase in FeCo-SiO2 nanocomposites
H Kumar, S Ghosh, P Srivastava, D Kabiraj, DK Avasthi, L Olivi, ...
Adv. Mater. Lett 4 (6), 390-397 2013

Ion beam-induced shaping of Ni nanoparticles embedded in a silica matrix: from spherical to prolate shape
H Kumar, S Ghosh, DK Avasthi, D Kabiraj, A Mcklich, S Zhou, H Schmidt, ...
Nanoscale research letters 6, 1-9 2011

Role of Coulomb blockade and spin-flip scattering in tunneling magnetoresistance of FeCo-Si-O nanogranular films
H Kumar, S Ghosh, D Brger, L Li, S Zhou, D Kabiraj, DK Avasthi, ...
Journal of Applied Physics 109 (7) 2011

Magnetic and field emission studies of atom beam sputtered Ni: SiO2 granular films
H Kumar, S Ghosh, DK Avasthi, D Kabiraj, NP Lalla, T Shripathi, JC Pivin
Vacuum 85 (2), 139-144 2010

Microstructure, electrical, magnetic, and extraordinary Hall effect studies in Ni: SiO2 nanogranular films synthesized by atom beam sputtering
H Kumar, S Ghosh, D Brger, S Zhou, D Kabiraj, DK Avasthi, R Grtzschel, ...
Journal of Applied Physics 107 (11) 2010

Controlled reduction of size of Ag nanoparticles embedded in teflon matrix by MeV ion irradiation
YK Mishra, VSK Chakravadhanula, U Schrmann, H Kumar, D Kabiraj, ...
Nuclear Instruments and Methods in Physics Research Section B: Beam 2008

MOST CITED SCHOLAR PUBLICATIONS

Improved hydrogen sensing behaviour in ion-irradiated Pd-Au alloy thin films
H Kumar, A Tripathi, AB Dey, M Gupta, R Krishna, DK Avasthi
Sensors and Actuators B: Chemical 301, 127006 2019
Citations: 27

Strain effects on the magnetic order of epitaxial FeRh thin films
H Kumar, DR Cornejo, SL Morelhao, S Kycia, IM Montellano, NR Alvarez, ...
Journal of Applied Physics 124 (8) 2018
Citations: 26

Compositional analysis of atom beam co-sputtered metal–silica nanocomposites by Rutherford backscattering spectrometry
H Kumar, YK Mishra, S Mohapatra, D Kabiraj, JC Pivin, S Ghosh, ...
Nuclear Instruments and Methods in Physics Research Section B: Beam 2008
Citations: 14

Stabilization of FeCo alloy phase in FeCo-SiO2 nanocomposites
H Kumar, S Ghosh, P Srivastava, D Kabiraj, DK Avasthi, L Olivi, ...
Adv. Mater. Lett 4 (6), 390-397 2013
Citations: 13

Magnetic and field emission studies of atom beam sputtered Ni: SiO2 granular films
H Kumar, S Ghosh, DK Avasthi, D Kabiraj, NP Lalla, T Shripathi, JC Pivin
Vacuum 85 (2), 139-144 2010
Citations: 12

Evidence of coexistence of ferromagnetic and antiferromagnetic phases in nearly equiatomic FeRh
H Kumar, MCA Fantini, DR Cornejo
IEEE transactions on magnetics 49 (8), 4506-4509 2013
Citations: 7

Role of nitrogen partial pressure, deposition rate and annealing on stability of β-W phase
SLMHK H. Singh, M. Gupta, P. Gupta, R. F. S. Penacchio
Applied Physics A 129 (312) 2023
Citations: 1