Title :
Exchange Interactions in Bcc Co: Implications for Temperature Dependence of TMR
Author :
Oset, Shawn J. ; Butler, W.H.
Author_Institution :
Dept. of Phys., Univ. of South Alabama, Mobile, AL
fDate :
6/1/2007 12:00:00 AM
Abstract :
Yuasa recently constructed Co/MgO/Co magnetic tunneling junctions (MTJs) with bcc Co(100) electrodes. These MTJs exhibited a magnetoresistance ratio of 410% at room temperature, and 507% at 20 K. The weak temperature dependence in comparison to Fe based electrodes led them to speculate that the weak temperature dependence may be due to exceptionally strong exchange interactions in bcc Co. Here we report on a theoretical investigation of the nearest neighbour exchange interactions in bcc Co
Keywords :
antiferromagnetic materials; cobalt; exchange interactions (electron); ferrimagnetic materials; ferromagnetic materials; magnesium compounds; magnetic moments; tunnelling magnetoresistance; Co-MgO; Co-MgO(100) MTJ; TMR; antiferromagnetic state; bcc cobalt electrodes; ferrimagnetic state; magnetic moments; nearest neighbour exchange interactions; tunneling magnetoresistance; Atomic measurements; Electrodes; Electrons; Elementary particle exchange interactions; Iron; Magnetic moments; Magnetic tunneling; Nearest neighbor searches; Temperature dependence; Tunneling magnetoresistance; Curie temperature; bcc Co; exchange interaction;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2007.894141
