Colossal Magnetoresistance is a Griffiths Singularity

Colossal magnetoresistance

We review recent experimental work falling under the broad classification of colossal magnetoresistance (CMR), which is magnetoresistance associated with a ferromagnetic-toparamagnetic phase transition. The prototypical CMR compound is derived from the parent compound, perovskite LaMnO3. When hole doped at a concentration of 20–40% holes/Mn ion, for instance by Ca or Sr substitution for La, the...

Colossal Magnetoresistance

Colossal magnetoresistance (CMR) effect was discovered among the manganese oxide class of materials, i.e. La1−xCaxMnO3. It shows large magnetoresistance by orders of magnitude, however several environmental requirements limit CMR toward general applications. Recently people have been focused on understanding a fundamental physics because of complex correlations between electron-lattice and elec...

Colossal Magnetoresistance

Colossal magnetocapacitance and colossal magnetoresistance in HgCr2S4.

We present a detailed study of the dielectric and charge transport properties of the antiferromagnetic cubic spinel HgCr2S4. Similar to the findings in ferromagnetic CdCr2S4, the dielectric constant of HgCr2S4 becomes strongly enhanced in the region below 60-80 K, which can be ascribed to polar relaxational dynamics triggered by the onset of ferromagnetic correlations. In addition, the observat...

Theory of colossal magnetoresistance

The history and recent developments in studying (colossal) magnetoresistance in perovskite manganese oxides is reviewed. We emphasize the growing evidence for strongly coupled spin, charge and lattice degrees of freedom. Together with disorder, these provide the microscopic driving forces for local and inhomogeneous textures. The modeling and experimental probes for localized charge–spin–lattic...