How can we use magneto-resistive materials for different applications?Which property is most useful and how temperature coefficient of resistance and magneto-resistance make them useful for bolometry?
Magnetoresistance (MR) effect is a well-known effect first discovered by Lord Kelvin in 1857 when he noticed the slight change in the electrical resistance of a piece of iron when he placed it in a magnetic field. The first application of the MR effect was a field-sensitive sensor reported by Hunt in 1971. Later, IBM introduced a MR head which could read and write bits on a MR strip and then eventually they turned it into the first hard disk drive in 1991. Nowadays MR is used in a wide range of devices from price tags and badge readers to magnetic tapes etc.
Since MR effect originates from the scattering of conducting electrons it inevitably shows temperature dependence. However its behavior is specific to the material used. In the following paper, for example, you can see a nearly linear decrease in the MR of LSMO and LBMO perovskite manganites as a function of temperature: Article Magnetoresistance temperature dependence of LSMO and LBMO pe...
For bolometric and infrared sensor applications, MR materials with high temperature coefficient of resistance near the metal-insulator transition temperature are highly useful as it allows detection of optical excitations by tuning the magnetic field. This criterion is well satisfied by some manganites such as LSMO (see for example: Article Magnetotransport of La0.70ca0.3-xsrxmno3 (Ag): A Potential R...
).
Thank you Sir I am working on LCMO material ............i have calculated temperature coefficient of resistance of LCMO bulk which comes out to be around 3% and trying to find its use for bolometery or magnetic refrigation?
My pleasure Navjyoti Boora
I think for the IR and bolometric applications, the fine tuning of the chemical potential is also important. Please check the papers I mentioned in my previous comment, they may give some ideas how to play with the stoichiometry and dimensionality (bulk vs. thin film) to get the best performance.
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