Roughness effects in uncompensated antiferromagnets

Charilaou, M.; Hellman, F.

doi:10.1063/1.4913594

Title: Roughness effects in uncompensated antiferromagnets

Journal Article · Wed Feb 25 00:00:00 EST 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4913594· OSTI ID:1512172

Charilaou, M. ^[1]; Hellman, F. ^[2]

Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division; Federal Inst. of Technology, Zurich (Switzerland). Lab. of Metal Physics and Technology
Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division

Monte Carlo simulations show that roughness in uncompensated antiferromagnets decreases not just the surface magnetization but also the net magnetization and particularly strongly affects the temperature dependence. In films with step-type roughness, each step creates a new compensation front that decreases the global net magnetization. The saturation magnetization decreases non-monotonically with increasing roughness and does not scale with the surface area. Roughness in the form of surface vacancies changes the temperature-dependence of the magnetization; when only one surface has vacancies, the saturation magnetization will decrease linearly with surface occupancy, whereas when both surfaces have vacancies, the magnetization is negative and exhibits a compensation point at finite temperature, which can be tuned by controlling the occupancy. Roughness also affects the spin-texture of the surfaces due to long-range dipolar interactions and generates non-collinear spin configurations that could be used in devices to produce locally modified exchange bias. Lastly, these results explain the strongly reduced magnetization found in magnetometry experiments and furthers our understanding of the temperature-dependence of exchange bias.

View Accepted Manuscript (DOE)

View Accepted Manuscript (Publisher)

Cite

Export

Save

Research Organization:: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

Grant/Contract Number:: AC02-05CH11231

OSTI ID:: 1512172

Alternate ID(s):: OSTI ID: 1228199

Journal Information:: Journal of Applied Physics, Vol. 117, Issue 8; ISSN 0021-8979

Publisher:: American Institute of Physics (AIP)Copyright Statement

Country of Publication:: United States

Language:: English

Citation Metrics:

Cited by: 19 works

Citation information provided by
Web of Science

References (39)

Pinned magnetization in the antiferromagnet and ferromagnet of an exchange bias system Fitzsimmons, M. R.; Kirby, B. J.; Roy, S. Physical Review B, Vol. 75, Issue 21 https://doi.org/10.1103/PhysRevB.75.214412	journal	June 2007
Microscopic model for exchange anisotropy de Almeida, J. R. L.; Rezende, S. M. Physical Review B, Vol. 65, Issue 9 https://doi.org/10.1103/PhysRevB.65.092412	journal	February 2002
Robust isothermal electric control of exchange bias at room temperature He, Xi; Wang, Yi; Wu, Ning Nature Materials, Vol. 9, Issue 7 https://doi.org/10.1038/nmat2785	journal	June 2010
Self‐consistent domain theory in soft‐ferromagnetic media. II. Basic domain structures in thin‐film objects van den Berg, H. A. M. Journal of Applied Physics, Vol. 60, Issue 3 https://doi.org/10.1063/1.337352	journal	August 1986
Spintronics: A Spin-Based Electronics Vision for the Future Wolf, S. A.; Awschalom, D. D.; Buhrman, R. A. Science, Vol. 294, Issue 5546, p. 1488-1495 https://doi.org/10.1126/science.1065389	journal	November 2001
Heisenberg-to-Ising crossover in a random-field model with uniaxial anisotropy Malozemoff, A. P. Physical Review B, Vol. 37, Issue 13 https://doi.org/10.1103/PhysRevB.37.7673	journal	May 1988
Dipolar effects in multilayers with interface roughness Vargas, P.; Altbir, D. Physical Review B, Vol. 62, Issue 10 https://doi.org/10.1103/PhysRevB.62.6337	journal	September 2000
Exchange anisotropy — a review Berkowitz, A. E.; Takano, Kentaro Journal of Magnetism and Magnetic Materials, Vol. 200, Issue 1-3 https://doi.org/10.1016/S0304-8853(99)00453-9	journal	October 1999
Mean-field simulation of metal oxide antiferromagnetic films and multilayers Charilaou, M.; Hellman, F. Physical Review B, Vol. 87, Issue 18 https://doi.org/10.1103/PhysRevB.87.184433	journal	May 2013
Electron-Mediated Ferromagnetic Behavior in $CoO / ZnO$ Multilayers Lee, H. -J.; Bordel, C.; Karel, J. Physical Review Letters, Vol. 110, Issue 8 https://doi.org/10.1103/PhysRevLett.110.087206	journal	February 2013
Anisotropie magnétique superficielle et surstructures d'orientation Néel, Louis Journal de Physique et le Radium, Vol. 15, Issue 4 https://doi.org/10.1051/jphysrad:01954001504022500	journal	January 1954
Crystalline and magnetic anisotropy of the 3 $d$ -transition metal monoxides MnO, FeO, CoO, and NiO Schrön, A.; Rödl, C.; Bechstedt, F. Physical Review B, Vol. 86, Issue 11 https://doi.org/10.1103/PhysRevB.86.115134	journal	September 2012
Exchange bias in nanostructures Nogués, J.; Sort, J.; Langlais, V. Physics Reports, Vol. 422, Issue 3 https://doi.org/10.1016/j.physrep.2005.08.004	journal	December 2005
Fast Monte Carlo method for magnetic nanoparticles Vargas, P.; Altbir, D.; d'Albuquerque e. Castro, J. Physical Review B, Vol. 73, Issue 9 https://doi.org/10.1103/PhysRevB.73.092417	journal	March 2006
Direct Measurement of Rotatable and Frozen CoO Spins in Exchange Bias System of $CoO / Fe / Ag (001)$ Wu, J.; Park, J. S.; Kim, W. Physical Review Letters, Vol. 104, Issue 21 https://doi.org/10.1103/PhysRevLett.104.217204	journal	May 2010
Exchange bias of the interface spin system at the Fe/MgO interface Fan, Y.; Smith, K. J.; Lüpke, G. Nature Nanotechnology, Vol. 8, Issue 6 https://doi.org/10.1038/nnano.2013.94	journal	June 2013
Depth Profile of Uncompensated Spins in an Exchange Bias System Roy, S.; Fitzsimmons, M. R.; Park, S. Physical Review Letters, Vol. 95, Issue 4 https://doi.org/10.1103/PhysRevLett.95.047201	journal	July 2005
Giant Magnetoresistance of (001)Fe/(001)Cr Magnetic Superlattices Baibich, M. N.; Broto, J. M.; Fert, A. Physical Review Letters, Vol. 61, Issue 21 https://doi.org/10.1103/PhysRevLett.61.2472	journal	November 1988
Mechanism of magnetization enhancement at CoO/permalloy interfaces Grytsyuk, Sergiy; Schwingenschlögl, Udo Applied Physics Letters, Vol. 103, Issue 7 https://doi.org/10.1063/1.4818507	journal	August 2013
Domain state model for exchange bias. I. Theory Nowak, U.; Usadel, K. D.; Keller, J. Physical Review B, Vol. 66, Issue 1 https://doi.org/10.1103/PhysRevB.66.014430	journal	July 2002
Magnetoelectronics Prinz, G. A. Science, Vol. 282, Issue 5394 https://doi.org/10.1126/science.282.5394.1660	journal	November 1998
Tuning the magnetic coupling across ultrathin antiferromagnetic films by controlling atomic-scale roughness Kuch, W.; Chelaru, L. I.; Offi, F. Nature Materials, Vol. 5, Issue 2 https://doi.org/10.1038/nmat1548	journal	January 2006
Exchange bias Nogués, J.; Schuller, Ivan K. Journal of Magnetism and Magnetic Materials, Vol. 192, Issue 2 https://doi.org/10.1016/S0304-8853(98)00266-2	journal	February 1999
Simple model for thin ferromagnetic films exchange coupled to an antiferromagnetic substrate Mauri, D.; Siegmann, H. C.; Bagus, P. S. Journal of Applied Physics, Vol. 62, Issue 7 https://doi.org/10.1063/1.339367	journal	October 1987
Interface reaction of NiO/NiFe and its influence on magnetic properties Yu, G. H.; Chai, C. L.; Zhu, F. W. Applied Physics Letters, Vol. 78, Issue 12 https://doi.org/10.1063/1.1343474	journal	March 2001
Anomalous magnetic thermodynamics in uncompensated collinear antiferromagnets Charilaou, M.; Hellman, F. EPL (Europhysics Letters), Vol. 107, Issue 2 https://doi.org/10.1209/0295-5075/107/27002	journal	July 2014
Surface-induced phenomena in uncompensated collinear antiferromagnets Charilaou, M.; Hellman, F. Journal of Physics: Condensed Matter, Vol. 27, Issue 8 https://doi.org/10.1088/0953-8984/27/8/086001	journal	February 2015
Mechanisms for exchange bias Stamps, R. L. Journal of Physics D: Applied Physics, Vol. 33, Issue 23 https://doi.org/10.1088/0022-3727/33/23/201	journal	November 2000
Generic source of perpendicular anisotropy in amorphous rare-earth–transition-metal films Fu, Hong; Mansuripur, Masud; Meystre, Pierre Physical Review Letters, Vol. 66, Issue 8 https://doi.org/10.1103/PhysRevLett.66.1086	journal	February 1991
Increased exchange anisotropy due to disorder at permalloy/CoO interfaces Moran, T. J.; Gallego, J. M.; Schuller, Ivan K. Journal of Applied Physics, Vol. 78, Issue 3 https://doi.org/10.1063/1.360225	journal	August 1995
Measurement of Spin-Wave Dispersion in NiO by Inelastic Neutron Scattering and Its Relation to Magnetic Properties Hutchings, M. T.; Samuelsen, E. J. Physical Review B, Vol. 6, Issue 9 https://doi.org/10.1103/PhysRevB.6.3447	journal	November 1972
Uncompensated Moments in the $MnPd / Fe$ Exchange Bias System Brück, Sebastian; Schütz, Gisela; Goering, Eberhard Physical Review Letters, Vol. 101, Issue 12 https://doi.org/10.1103/PhysRevLett.101.126402	journal	September 2008
Finite size effects on the moment and ordering temperature in antiferromagnetic CoO layers Tang, Y. J.; Smith, David J.; Zink, B. L. Physical Review B, Vol. 67, Issue 5 https://doi.org/10.1103/PhysRevB.67.054408	journal	February 2003
Exchange-biased magnetic tunnel junctions and application to nonvolatile magnetic random access memory (invited) Parkin, S. S. P.; Roche, K. P.; Samant, M. G. Journal of Applied Physics, Vol. 85, Issue 8 https://doi.org/10.1063/1.369932	journal	April 1999
Random-field model of exchange anisotropy at rough ferromagnetic-antiferromagnetic interfaces Malozemoff, A. P. Physical Review B, Vol. 35, Issue 7 https://doi.org/10.1103/PhysRevB.35.3679	journal	March 1987
An ab initio cluster study of the magnetic properties of the CoO(001) surface Staemmler, Volker; Fink, Karin Chemical Physics, Vol. 278, Issue 2-3 https://doi.org/10.1016/S0301-0104(02)00389-0	journal	May 2002
Evidence of modified ferromagnetism at a buried Permalloy/CoO interface at room temperature Roy, S.; Sanchez-Hanke, C.; Park, S. Physical Review B, Vol. 75, Issue 1 https://doi.org/10.1103/PhysRevB.75.014442	journal	January 2007
Mechanisms of exchange anisotropy (invited) Malozemoff, A. P. Journal of Applied Physics, Vol. 63, Issue 8 https://doi.org/10.1063/1.340591	journal	April 1988
Scaling Approach to the Magnetic Phase Diagram of Nanosized Systems d'Albuquerque e. Castro, J.; Altbir, D.; Retamal, J. C. Physical Review Letters, Vol. 88, Issue 23 https://doi.org/10.1103/PhysRevLett.88.237202	journal	May 2002

Cited By (6)

Magnetocaloric effect in cubically anisotropic magnets Hu, Yong; Hu, Tianyi; Chi, Xiaodan Applied Physics Letters, Vol. 114, Issue 2 https://doi.org/10.1063/1.5081130	journal	January 2019
Influence of atomic roughness at the uncompensated Fe/CoO(111) interface on the exchange-bias effect Wu, Rui; Xue, Mingzhu; Maity, Tuhin Physical Review B, Vol. 101, Issue 1 https://doi.org/10.1103/physrevb.101.014425	journal	January 2020
Imaging uncompensated moments and exchange-biased emergent ferromagnetism in FeRh thin films Gray, Isaiah; Stiehl, Gregory M.; Heron, John T. Physical Review Materials, Vol. 3, Issue 12 https://doi.org/10.1103/physrevmaterials.3.124407	journal	December 2019
Influence of atomic roughness at the uncompensated Fe/CoO(111) interface on the exchange-bias effect Wu, R.; Xue, M.; Maity, T. Apollo - University of Cambridge Repository https://doi.org/10.17863/cam.48044	text	January 2020
Imaging uncompensated moments and exchange-biased emergent ferromagnetism in FeRh thin films Gray, Isaiah; Stiehl, Gregory M.; Heron, John T. arXiv https://doi.org/10.48550/arxiv.1906.07243	text	January 2019
Influence of Atomic Roughness at The Uncompensated Fe/CoO (111) Interface on Exchange Bias Effect Wu, Rui; Xue, Mingzhu; Maity, Tuhin arXiv https://doi.org/10.48550/arxiv.2001.01320	text	January 2020