Interface Characterization of Current-Perpendicular-to-Plane Spin Valves Based on Spin Gapless Semiconductor Mn2CoAl

Employing the first-principles calculations within density functional theory (DFT) combined with the nonequilibrium Green’s function, we investigated the interfacial electronic, magnetic, and spin transport properties of Mn2CoAl/Ag/Mn2CoAl current-perpendicular-to-plane spin valves (CPP-SV). Due to the interface rehybridization, the magnetic moment of the interface atom gets enhanced. Further analysis on electronic structures reveals that owing to the interface states, the interface spin polarization is decreased. The largest interface spin polarization (ISP) of 78% belongs to the MnCoT-terminated interface, and the ISP of the MnMnT1-terminated interface is also as high as 45%. The transmission curves of Mn2CoAl/Ag/Mn2CoAl reveal that the transmission coefficient at the Fermi level in the majority spin channel is much higher than that in the minority spin channel. Furthermore, the calculated magnetoresistance (MR) ratio of the MnCoT-terminated interface reaches up to 2886%, while that of the MnMnT1-terminated interface is only 330%. Therefore, Mn2CoAl/Ag/Mn2CoAl CPP-SV with an MnCo-terminated interface structure has a better application in a spintronics device.

[1]  Jinlong Yang,et al.  First principles design of spintronics materials , 2016 .

[2]  Claudia Felser,et al.  Simple rules for the understanding of Heusler compounds , 2011 .

[3]  Xiaolin Wang,et al.  Proposal for a new class of materials: spin gapless semiconductors. , 2008, Physical review letters.

[4]  Zhenxiang Cheng,et al.  Rare earth-based quaternary Heusler compounds MCoVZ (M = Lu, Y; Z = Si, Ge) with tunable band characteristics for potential spintronic applications , 2017, IUCrJ.

[5]  K. Hono,et al.  Bulk and interfacial scatterings in current-perpendicular-to-plane giant magnetoresistance with Co2Fe(Al0.5Si0.5) Heusler alloy layers and Ag spacer , 2010 .

[6]  S. Blügel,et al.  Conditions for spin-gapless semiconducting behavior in Mn2CoAl inverse Heusler compound , 2014 .

[7]  K. Özdoğan,et al.  Generalized Slater-Pauling rule for the inverse Heusler compounds , 2012, 1210.5816.

[8]  Jian Wang,et al.  Ab initio modeling of quantum transport properties of molecular electronic devices , 2001 .

[9]  Kazuhiro Hono,et al.  Enhancement of giant magnetoresistance by L21 ordering in Co2Fe(Ge0.5Ga0.5) Heusler alloy current-perpendicular-to-plane pseudo spin valves , 2013 .

[10]  A. Gloskovskii,et al.  Direct observation of half-metallicity in the Heusler compound Co2MnSi , 2014, Nature Communications.

[11]  Hong Guo,et al.  Nonlinear spin current and magnetoresistance of molecular tunnel junctions. , 2006, Physical review letters.

[12]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[13]  Chengchun Tang,et al.  Half-metallic full-Heusler compound Ti2NiAl: A first-principles study , 2011 .

[14]  M. Shirai,et al.  Extensive study of giant magnetoresistance properties in half-metallic Co2(Fe,Mn)Si-based devices , 2012 .

[15]  N. Papanikolaou,et al.  Slater-Pauling behavior and origin of the half-metallicity of the full-Heusler alloys , 2002 .

[16]  H. Akbarzadeh,et al.  Half-metallicity at the Heusler alloy Co2Cr0.5Fe0.5Al(001) surface and its interface with GaAs(001) , 2009, Journal of physics. Condensed matter : an Institute of Physics journal.

[17]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[18]  Half-metallicity and Slater-Pauling behavior in the ferromagnetic Heusler alloys , 2004, cond-mat/0408068.

[19]  S. Blugel,et al.  First-principles calculations of exchange interactions, spin waves, and temperature dependence of magnetization in inverse-Heusler-based spin gapless semiconductors , 2015, 1505.03632.

[20]  C. Walle,et al.  First-principles calculations for defects and impurities: Applications to III-nitrides , 2004 .

[21]  C. Tsang,et al.  Fabrication and Recording Study of All-Metal Dual-Spin-Valve CPP Read Heads , 2006, IEEE Transactions on Magnetics.

[22]  H. Akbarzadeh,et al.  First principle study of Co2MnSi/GaAs(001) heterostructures , 2007 .

[23]  Hong Chen,et al.  Magnetism and half-metallicity in bulk and (1 0 0) surface of Heusler alloy Ti2CoAl with Hg2CuTi-type structure , 2013 .

[24]  Stuart A. Wolf,et al.  Spintronics: A Spin-Based Electronics Vision for the Future , 2001, Science.

[25]  T. Koganezawa,et al.  Structure and magnetoresistance of current-perpendicular-to-plane pseudo spin valves using Co2Mn(Ga0.25Ge0.75) Heusler alloy , 2013 .

[26]  M. Shirai,et al.  Mechanism of large magnetoresistance in Co 2 MnSi / Ag / Co 2 MnSi devices with current perpendicular to the plane , 2010 .

[27]  S. Hatfield,et al.  Interaction of Mn with GaAs and InSb: incorporation, surface reconstruction and nano-cluster formation , 2014, Journal of physics. Condensed matter : an Institute of Physics journal.

[28]  Hong Chen,et al.  Structural stability, half-metallicity and magnetism of the CoFeMnSi/GaAs(0 0 1) interface , 2015 .

[29]  Hong Chen,et al.  Thermodynamic stability, magnetism and half metallicity of Mn2CoAl/GaAs(0 0 1) interface , 2015 .

[30]  G. Fecher,et al.  Realization of spin gapless semiconductors: the Heusler compound Mn2CoAl. , 2012, Physical review letters.

[31]  K. Özdoğan,et al.  Search for spin gapless semiconductors: The case of inverse Heusler compounds , 2012, 1210.5355.

[32]  Hong Chen,et al.  The effect of disorder on electronic and magnetic properties of quaternary Heusler alloy CoFeMnSi with LiMgPbSb-type structure , 2015 .