Disorder effects in the S1⁄41 antiferromagnetic spin ladder CaV2O4

S. R. GUITARRA; A. CANEIRO; D. NIEBIESKIKWIAT

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 392 p. 63 - 67

0304-8853

We study the physical properties of the antiferromagnetic spin ladder CaV2O4 (CVO) and the Y-doped related compound Ca0.9Y0.1V2O4. In the latter, X-ray diffraction demonstrates the segregation of a small amount of a vanadium?perovskite impurity phase, leading to the formation of V vacancies within the main CVO-type structure. The 1D character of this calcium?vanadite enhances the influence of the va- cancies on the electric and magnetic properties of Ca0.9Y0.1V2O4. Electrical transport is characterized by a variable-range hopping mechanism determined by the charging energy of nm-sized segments of V chains delimited by V vacancies, i.e. a Coulomb gap is formed at the Fermi level. These vacancies also locally affect the magnetic correlations, breaking the long-range AFM order observed in CaV2O4 and producing exchange bias when the Y-doped sample is cooled with an applied magnetic field.