Determination of rotatable and frozen CoO spins and their relationship to exchange bias in CoO/Fe/Ag(001)

Journal Article · Wed Feb 10 04:00:00 EST 2010 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.104.217204· OSTI ID:983290

Wu, J; Park, J; Kim, W; Arenholz, E; Liberati, M; Scholl, A; Wu, Y; Hwang, C; Qiu, Z

The exchange bias of epitaxially grown CoO/Fe/Ag(001) was investigated using X-ray Magnetic Circular Dichroism (XMCD) and X-ray Magnetic Linear Dichroism (XMLD) techniques. A direct XMLD measurement on the CoO layer during the Fe magnetization reversal shows that the CoO compensated spins are rotatable at thinner thickness and frozen, i.e. fixed in direction to the lattice, at larger thickness. By a quantitative determination of the rotatable and frozen CoO spins as a function of the CoO film thickness, we find the remarkable result that the exchange bias is well established before frozen spins are detectable in the CoO film, contrary to the common assumption that the majority of antiferromagnetic spins need to be frozen to generate the exchange bias. We further show that the rotatable/frozen CoO spins are uniformly distributed in the CoO film.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Advanced Light Source Division; Materials Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 983290
• Report Number(s): LBNL-3440E
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DICHROISM
MAGNETIC CIRCULAR DICHROISM
MAGNETIZATION
THICKNESS