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Magnetic exchange bias of more than 1 tesla in a natural mineral intergrowth

McEnroe, Suzanne A. and Carter-Stiglitz, Brian and Harrison, Richard J. and Robinson, Peter and Fabian, Karl and McCammon, Catherine (2007) Magnetic exchange bias of more than 1 tesla in a natural mineral intergrowth. NATURE NANOTECHNOLOGY, 2 (10). pp. 631-634.

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Magnetic exchange bias is a phenomenon whereby the hysteresis loop of a `soft' magnetic phase is shifted by an amount H E along the applied field axis owing to its interaction with a `hard' magnetic phase. Since the discovery of exchange bias fifty years ago(1), the development of a general theory has been hampered by the uncertain nature of the interfaces between the hard and soft phases, commonly between an antiferromagnetic phase and a ferro- or ferrimagnetic phase. Exchange bias continues to be the subject of investigation because of its technological applications and because it is now possible to manipulate magnetic materials at the nanoscale(2-6). Here we present the first documented example of exchange bias of significant magnitude (> 1 T) in a natural mineral. We demonstrate that exchange bias in this system is due to the interaction between coherently intergrown magnetic phases formed through a natural process of phase separation during slow cooling over millions of years. Transmission electron microscopy studies show that these intergrowths have a known crystallographic orientation with a known crystallographic structure and that the interfaces are coherent(7-14).

Item Type:Article
Subjects:Physical Science > Nanomagnetics
Material Science > Nanostructured materials
ID Code:2260
Deposited By:Anuj Seth
Deposited On:06 Jan 2009 12:56
Last Modified:19 Jan 2009 15:57

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