Abstract
It is well established that the resistance of manganites is a function of magnetization. In a conventional experiment, the magnetization is changed by the application of a magnetic field, and a resistance change is measured. The manganites show two different forms of colossal magnetoresistance: that which is associated with very narrow domain walls in polycrystalline samples with grain boundaries, and that associated with magnetic ordering near to the transition temperature. Although the former only requires low fields, it is also only observed at low temperatures. Hence there is a real need to reduce the magnetic field required to observe the effect near to the transition where, currently, fields of the order of 1 T are required. An alternative approach is to change the state of magnetization by injection of spin-polarized carriers. We have recently taken out a patent which describes a general technique which may be used to inject carriers: a manganite permalloy heterostructure. This paper discusses the background to this approach in terms of the band structures of permalloy and manganite, and the way in which the switching field may be reduced. We present results from our experimental programme, which is attempting to realize a structure in current perpendicular to plane geometry to study spin injection.
Original language | English |
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Pages (from-to) | 1681-1692 |
Number of pages | 12 |
Journal | Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |
Volume | 356 |
Issue number | 1742 |
DOIs | |
Publication status | Published - 15 Jul 1998 |
Keywords
- Colossal magnetoresistance
- Device
- Heterostructures
- LaCaMnO
ASJC Scopus subject areas
- General Mathematics
- General Engineering
- General Physics and Astronomy