Novel behaviors of coercivity in GdFeCo/Hf/MgO heterostructure

It is commonly known that the coercivity (Hc) of the rare-earth/transition-metal (RE–TM) compound is tuned based on the varying RE content as compared to the TM component. The drawback of this approach is that the Hc changes are permanent. In this work, we investigate the coercivity behaviors of the GdFeCo/Hf/MgO heterostructure where the heavy metal Hf layer is inserted in the middle not only to convert charge current into spin current but also to prevent the oxygen diffusion effect. A strong geometry dependence of coercivity detected on Hall bar devices is attributed to the intrinsic properties of GdFeCo and elucidates that the oxidation issue from MgO on GdFeCo is prevented. By selecting a proper Gd content, we demonstrate that the coercivity can be altered flexibly in a wide range [Formula: see text] via electric current. We develop a simple model to simulate the roles of Joule heating and spin–orbit torques in the novel behaviors of coercivity. It is verified that the excellent magnetic characteristics of GdFeCo are still preserved while manipulating coercivity by the electric current. Our findings broaden the new magnetic behaviors of RE–TM alloys, making them attractive for tunable magnetic anisotropy.

[1]  A. Berger,et al.  Suppression of Coercivity in Nanoscale Graded Magnetic Materials , 2021, Physical Review Applied.

[2]  Ke Wang,et al.  Tuning Perpendicular Magnetic Properties of Sputtered Rare-Earth Transition Metal GdFeCo Alloy Films , 2021, Journal of Superconductivity and Novel Magnetism.

[3]  L. Ye,et al.  Sense current dependent coercivity and magnetization relaxation in Gd-Fe-Co Hall bar , 2020, Journal of Magnetism and Magnetic Materials.

[4]  Ke Wang,et al.  Thermal degradation behavior of amorphous GdFeCo alloy films with perpendicular anisotropy , 2021 .

[5]  K. Zvezdin,et al.  Unusual behavior of coercivity in Hf/GdFeCo bilayer with MgO cap layer by electric current , 2020 .

[6]  J. Bokor,et al.  Progress towards ultrafast spintronics applications , 2020 .

[7]  Jongill Hong,et al.  Impact of Spin-Orbit Torque on Spin-Transfer Torque Switching in Magnetic Tunnel Junctions , 2020, Scientific Reports.

[8]  Kyung-Jin Lee,et al.  Spin-orbit Torque Switching of Perpendicular Magnetization in Ferromagnetic Trilayers , 2020, Scientific Reports.

[9]  Weiming Lü,et al.  Asymmetric Spin-Orbit-Torque-Induced Magnetization Switching With a Noncollinear In-Plane Assisting Magnetic Field , 2019, Physical Review Applied.

[10]  Ke Wang,et al.  Thickness and substrate effects on the perpendicular magnetic properties of ultra-thin TbFeCo films , 2019, Surface and Coatings Technology.

[11]  G. Beach,et al.  Temperature dependence of the Dzyaloshinskii-Moriya interaction in Pt/Co/Cu thin film heterostructures , 2018, Applied Physics Letters.

[12]  T. Ostler,et al.  Ultrafast double magnetization switching in GdFeCo with two picosecond-delayed femtosecond pump pulses , 2018, Applied Physics Letters.

[13]  Jonghyuk Kim,et al.  Spin-orbit torques associated with ferrimagnetic order in Pt/GdFeCo/MgO layers , 2018, Scientific Reports.

[14]  Jong Min Lee,et al.  Anomalous spin-orbit torque switching due to field-like torque–assisted domain wall reflection , 2017, Science Advances.

[15]  Jiecai Han,et al.  Spin transfer torque switching in exchange-coupled amorphous GdFeCo/TbFe bilayers for thermally assisted MRAM application , 2017 .

[16]  J. Bokor,et al.  Ultrafast magnetization reversal by picosecond electrical pulses , 2016, Science Advances.

[17]  J. Bokor,et al.  Ultrafast magnetic switching of GdFeCo with electronic heat currents , 2016, 1609.05155.

[18]  Jianping Wang,et al.  Picosecond all-optical switching of magnetic tunnel junctions , 2016, 1607.04615.

[19]  T. Ono,et al.  Modulation of the magnetic domain size induced by an electric field , 2016, 1604.02770.

[20]  H. Awano,et al.  Enhanced perpendicular coercivity of ultrathin perpendicularly magnetized Tb–Fe–Co films on silicon substrates using a thin Pt underlayer , 2016 .

[21]  William Legrand,et al.  Coherent Subnanosecond Switching of Perpendicular Magnetization by the Fieldlike Spin-Orbit Torque without an External Magnetic Field , 2015 .

[22]  Jianping Wang,et al.  Spin Hall switching of the magnetization in Ta/TbFeCo structures with bulk perpendicular anisotropy , 2015, 1501.02294.

[23]  Jiawen Weng,et al.  The study of ultrafast magnetization reversal across magnetization compensation temperature in GdFeCo film induced by femtosecond laser pulses , 2014 .

[24]  S. Wolf,et al.  Strain-induced enhancement of coercivity in amorphous TbFeCo films , 2013, 1307.0057.

[25]  S. Iwata,et al.  Spin Transfer Torque Switching of Amorphous GdFeCo With Perpendicular Magnetic Anisotropy for Thermally Assisted Magnetic Memories , 2012, IEEE Transactions on Magnetics.

[26]  S. Moussaoui,et al.  Demonstration of laser induced magnetization reversal in GdFeCo nanostructures , 2012 .

[27]  Arata Tsukamoto,et al.  Crystallographically amorphous ferrimagnetic alloys: Comparing a localized atomistic spin model with experiments , 2011 .

[28]  A. Vindigni,et al.  (Ir-)Reversibility and thermal equilibrium in magnetic domain pattern formation in ultra-thin ferromagnetic films , 2010, 1009.1815.

[29]  S. Nakagawa,et al.  Improvement of stress-induced magnetization reversal process of DyFeCo thin films , 2008 .

[30]  Arata Tsukamoto,et al.  Ultrafast spin dynamics across compensation points in ferrimagnetic GdFeCo: The role of angular momentum compensation , 2006 .

[31]  E. Shypil,et al.  A study of magnetization in exchange-coupled FM/Gd bilayers , 2005 .

[32]  David Jenkins,et al.  Optical and magneto-optical characterization of TbFeCo and GdFeCo thin films for high-density recording , 2003 .

[33]  Tadahiko Hirai,et al.  Magnetic tunnel junction device with perpendicular magnetization films for high-density magnetic random access memory , 2002 .

[34]  H. Shieh,et al.  Positive giant magnetoresistance in ferrimagnetic/Cu/ferrimagnetic films , 2001 .

[35]  M. Kaneko.  Magnetic multilayer films for high-density magneto-optical recording , 1995 .

[36]  Masahiko Kaneko,et al.  Magneto-optical recording on Pt/Co and GdFeCo/TbFeCo disks using a green laser , 1993 .

[37]  B. Johansson,et al.  3d-5d band magnetism in rare earth-transition metal intermetallics: total and partial magnetic moments of the RFe2 (R=Gd-Yb) Laves phase compounds , 1991 .

[38]  A. Gangulee,et al.  Magnetic properties of the3dtransition metals in the amorphous ternary alloys:Gd0.2(FexCo1−x)0.8,Gd0.2(CoxNi1−x)0.8, andGd0.2(FexNi1−x)0.8 , 1980 .