Liu yukuai, yin yuewei, and li xiaoguang hefei national laboratory for physical sciences at microscale, department of physics, university of science and technology of china, hefei 230026, p. The negative colossal magnetoresistance cmr of manganitecobaltite and. The magnetoresistance of conventional materials enables changes in resistance of up to 5%, but materials featuring cmr may demonstrate resistance changes by orders of magnitude. Relation between thickness, crystallite size and magnetoresistance. Hopping from mniii to neighboring mniv is therefore facilitated. This arises because of strong mutual coupling of spin, charge and lattice degrees of freedom. The prototypical cmr compound is derived from the parent compound, perovskite lamno 3. The tremendous technological potential of the giant magnetoresistive gmr effect was recognized when the nobel prize in physics was awarded to albert fert. Physical properties and appications of colossal magnetoresistance. Colossal magnetoresistance is a property with practical applications in a wide array of electronic tools including magnetic sensors and magnetic ram. Spin correlations and colossal magnetoresistance in hgcr 2.
Nondestructive eddy current testing ect is widely used to examine structural defects in ferromagnetic pipe in the oil and gas industry. Colossal magnetoresistance manganites and related prototype devices. A giant magnetoresistance sensor for high magnetic field measurements. Pdf highfrequency cmrbscalar sensor for pulsed magnetic. Pulsed magnetic field measurement system based on colossal magnetoresistance bscalar sensors for railgun investigation. What is the mechanism for the colossal magnetoresistance. Since the discovery of the giant magnetoresistance gmr effect in 1988, spintronics has been presented as a new technology paradigm, awarded by the nobel. Colossal magnetoresistance cmr phenomena are observed in the perovskitetype holedoped manganites in which the doubleexchange ferromagnetic metal phase and the chargeorbital ordered. For the love of physics walter lewin may 16, 2011 duration. Spectroscopic data were processed by the avantage v.
Colossal magnetoresistance of ferromagnetic manganites. Sensors free fulltext giant magnetoresistance sensors. Colossal magnetoresistance has been predominantly discovered in manganesebased perovskite oxides. Implementation of giant magnetoresistance gmr sensors as magnetic field sensors to. Near the magnetic transition, when the spins are tending to line up, switching on a magnetic. Near room temperature the electron transport exhibits an ordinary semiconducting behavior. National basic research program of china contract nos. Euin 2 as 2 is metallic and magnetoresistive, as is the isostructural phosphide, and both compounds have coincident resistivity and magnetic ordering transitions, consistent with the observation of colossal magnetoresistance. Pb exhibiting colossal magnetoresistance cmr effect is one of strongly correlated electron systems with.
Colossal magnetoresistance cmr is a property of some materials, mostly manganesebased perovskite oxides, that enables them to dramatically change their electrical resistance in the presence of a magnetic field. The main application of gmr is magnetic field sensors, which are used to. Increasing the bond distortion lowers t m and enhances \t,h\. Pulsed magnetic field measurement system based on colossal.
The system is fully controlled by labview software. Magnetoresistance an overview sciencedirect topics. The magnetic field pulse characteristics are measured using colossal magnetoresistancebscalar sensors placed at different depths inside the rails of the accelerator. The software controlling the operation of the second supply source.
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