Anomalous Hall effect in the high-temperature ferrimagnetic semiconductors BaFe2 +/- xRu4 -/+ xO11

作者：Shlyk L^*; Niewa R; De Long L E

来源：Physical Review B, 2010, 82(13): 134432.

DOI：10.1103/PhysRevB.82.134432

Field and temperature dependences of the magnetic and transport properties of single crystals of BaFe2+xRu4-xO11 (x=0.5, 0.9, 1.4) R-type ferrites are reported. A wide homogeneity range of Ru/Fe compositions allows to tune the strength of the anomalous Hall effect (AHE), the width of the semiconducting gap (Delta), and the temperature of magnetic ordering (T-C) within one structural family. These parameters are enhanced for higher Fe content. A large Hall resistivity rho(xy)=77 mu Omega cm observed in single-crystal BaFe3.4Ru2.6O11 at 300 K is several orders of magnitude large than that observed for bulk magnetic materials, and comparable to the Hall resistivity of thin films of magnetite. The anomalous Hall coefficient R-s changes sign at a characteristic temperature T* that depends on the Fe/Ru ratio, which we attribute to variations in the electronic band structure. The Rs vs longitudinal resistivity (rho(xx)) dependence of BaFe3.4Ru2.6O11 can be described in terms of negative skew and positive side-jump scattering contributions that differ above and below T*. The very small side jump Delta y estimated from the contribution to the AHE that is quadratic in rho(xx) suggests that the AHE is caused by a Karplus-Luttinger (Berry phase) mechanism.

• 出版日期2010-10-20