Electron transport and magnetic properties of rare-earth ortho-titanites and -vanadites, LnTiO3 and LnVO3

Abstract

Electron transport and magnetic properties of a number of rare‐earth ortho‐titanites, LnTiO3 (Ln rare‐earth or Y), and ortho‐vanadites, LnVO3, are studied in detail. The results are discussed in terms of Goodenough's phenomenological phase diagram. Properties of various transition metal oxide perovskites, LnBO3 (B transition metal), are compared.

Spectroscopic investigations of the electronic structure and metal-insulator transitions in a Mott-Hubbard systemLa1−xCaxMaiti1, Sarma2 2000Phys. Rev. B7619441View full textAdd to dashboardCite

“…The effective ionic radius of Ca 2ϩ ͑1.34 Å͒ is close to that of La 3ϩ ͑1.36 Å͒. 24 The crystal structures of the two end members LaVO 3 and CaVO 3 are both distorted perovskite type [12][13][14][15][16][17][18]25 with similar V-O-V bond angle (158°in LaVO 3 and 160°in CaVO 3 ). 26,27 Thus, Ca substitution in LaVO 3 dopes hole states without any significant modification in the crystal structure and, consequently, in the bandwidth.…”

“…Most of the oxides studied have the perovskite structure, because of the possibility of charge carrier doping in this structure type by chemical, heterovalent substitution over a wide range of compositions without breaking the basic structural network. There are several reports on the transport and magnetic properties and electronic structures of such TM oxides, such as La 1Ϫx Sr x TiO 3 , 1,5-7 Y 1Ϫx Ca x TiO 3 , [8][9][10] La 1Ϫx Sr x VO 3 , [11][12][13][14][15][16][17][18][19][20][21] and Y 1Ϫx Ca x VO 3 . 22 Ca or Sr substitution, besides doping holes in these systems, also leads to a change in the TM-O-TM bond angle, which is an important parameter in tuning the bandwidth (W).…”

“…LaVO 3ϩ␦ is an antiferromagnetic insulator with a Néel temperature (T N ) varying from 128 K to 145 K depending on the exact oxygen stoichiometry. [15][16][17][18][19][20][21] The resis-tivity measurements show an activated conduction with an activation energy of 0.14 eV, 19 while optical measurements suggest a charge excitation gap of about 1.1 eV. 23 Despite the wide variation in magnetic properties, the transport properties have been found to remain relatively unaltered with the extent of oxygen nonstoichiometry, ␦.…”

An Investigation of the Magnetic Properties of Sm1−xTiO3forx=0.03, 0.05, and 0.10: Magnetic Structure Determination of Sm0.97TiO3by Short-Wavelength Neutron Diffraction on Single Crystals

“…A remarkable variation in the magnetic properties as a function of decreasing rare earth radius exists, ranging from antiferromagnetic Ti-Ti coupling for R"La, Ce, Pr, and Nd to ferromagnetic Ti-Ti coupling for R"Gd-Lu, Y (5)(6)(7)(8). In spite of the interesting position of Sm in the series, evidence for any type of magnetic ordering for the R"Sm compound had remained elusive (9). Until recently, however, there has been one published report indicating that SmTiO undergoes some type of ordering phenomenon at &50 K. Despite this, a detailed investigation into the magnetic properties as well as the magnetic structure determination for this compound has not been performed (10).…”

On the Valence State of Iron in Sr0.52+Ca0.52+Fe0.54+ Me0.54+O32−

“…The electric and magnetic properties of a series of these oxides with a 3d transition metal for the B-site can be understood by the schematic energy diagram proposed by Goodenough [ 1, 21. I n such a picture the eg orbitals of the B-cation form cr bonds with Op orbitals whereas the cation tzg orbitals form weaker n bonds with Op orbitals [3]. SrFeO, is well known as the stoichiometric oxide with cubic perovskite structure containing not Fez+ but only Fe4+ ions.…”