Structural and magnetic properties of Cr-diluted CoFeB

The crystallization process and the magnetization of Cr diluted CoFeB were investigated in both ribbon samples and thin film samples with Cr content up to 30 at. %. A primary crystallization of bcc phase from an amorphous precursor in ribbon samples was observed when the annealing temperature rose between 421 °C and 456 °C, followed by boron segregation at temperatures between 518 °C and 573 °C. The two onset crystallization temperatures showed strong dependences on both Cr and B concentrations. The impact of Cr concentration on the magnetic properties including a reduced saturation magnetization and an enhanced coercive field was also observed. The magnetizations of both ribbon samples and thin film samples were well fitted using the generalized Slater-Pauling curve with modified moments for B (−0.94 μB) and Cr (−3.6 μB). Possible origins of the enhanced coercive field were also discussed. We also achieved a damping parameter in CoFeCrB thin films at the same level as Co40Fe40B20, much lower than the val...

[1]  S. Yuasa,et al.  Giant tunneling magnetoresistance in MgO-based magnetic tunnel junctions and its industrial applications , 2006, 2006 IEEE Nanotechnology Materials and Devices Conference.

[2]  S. Yuasa,et al.  Reduction in switching current using a low-saturation magnetization Co–Fe–(Cr, V)–B free layer in MgO-based magnetic tunnel junctions , 2009 .

[3]  S. Wolf,et al.  Interfacial perpendicular magnetic anisotropy and damping parameter in ultra thin Co2FeAl films , 2013 .

[4]  J. Slonczewski.  Currents and torques in metallic magnetic multilayers , 2002 .

[5]  S. Mahajan,et al.  Coercivity mechanisms in Fe‐Cr‐Co magnet alloys , 1982 .

[6]  Michael E. McHenry,et al.  Amorphous and nanocrystalline materials for applications as soft magnets , 1999 .

[7]  Stuart A. Wolf,et al.  Spintronics : A Spin-Based Electronics Vision for the Future , 2009 .

[8]  M. Sostarich.  Generalized Slater–Pauling curve and the role of metalloids in Fe‐based amorphous alloys , 1990 .

[9]  A. Ruban,et al.  First-principles study of elastic properties of Cr- and Fe-rich Fe-Cr alloys , 2011 .

[10]  Peter Švec,et al.  Influence of isochronal annealing on the microstructure and magnetic properties of Cu-free HITPERM Fe40.5Co40.5Nb7B12 alloy , 2012 .

[11]  M. R. Khan,et al.  Magnetic properties and microstructures of CoNiCr and CoFeCr thin films , 1991 .

[12]  R. Sherwood,et al.  Origin of coercivity in a Cr‐Co‐Fe alloy (chromindur) , 1978 .

[13]  S. Yuasa,et al.  Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel junctions , 2004, Nature materials.

[14]  Ming-Jinn Tsai,et al.  Interfacial and annealing effects on magnetic properties of CoFeB thin films , 2006 .

[15]  V. L. Moruzzi,et al.  Generalized Slater-Pauling curve for transition-metal magnets , 1983 .

[16]  J. Livingston.  A review of coercivity mechanisms (invited) , 1981 .

[17]  C. You,et al.  Boron segregation in crystallized MgO/amorphous-Co40Fe40B20 thin films , 2008 .

[18]  J. Coey,et al.  Low magnetisation alloys for in-plane spin transfer torque devices , 2012 .

[19]  C. Lai,et al.  Reduction in critical current density by tuning damping constants of CoFeB for spin-torque-transfer switching , 2009 .

[20]  A. Panchula,et al.  Giant tunnelling magnetoresistance at room temperature with MgO (100) tunnel barriers , 2004, Nature materials.

[21]  Gang Xiao,et al.  Ferromagnetic resonance and damping properties of CoFeB thin films as free layers in MgO-based magnetic tunnel junctions , 2011 .

[22]  G. Thomas,et al.  Microstructure and magnetic properties of Fe‐Cr‐Co‐V alloys , 1978 .

[23]  T. Chin,et al.  High Coercivity Fe-Cr-Co Thin Films by Vacuum Evaporation , 1991 .