Characteristics of Magnetic Properties of Substituted Hexagonal Ferrites
Vladimir Jancarik, Anna Gruskova, Jozef Slama, Rastislav Dosoudil, Alvaro Gonzalez, Guillermo Mendoza
DOI:
Abstract
The samples of barium hexaferrite BaFe12-2x(Me1Me2)xO19with x from 0.0 to 0.6 were prepared by variousmethods. The cationic preference of mainly divalent Me1= Zn, Co, Ni, Sn ions and tetravalent Me2= Ti, Zr, Ir, Sn, Ru ionsand their combinations in substituted Ba ferrites was investigated. The substitutions were performed to reduce the grain sizeand high magnetic uniaxial anisotropy field of the M-type Ba ferrite without affecting the magnetic polarisation. The goal isto reach the properties of ferrite proper for high-density magnetic recording and microwave absorption devices. Magneticproperties were determined as a function of the substitution level x. The specific saturation magnetic polarisation Js–m andremanence Js–rincreased with small x due to the substitution of non-magnetic and less magnetic ions in 4f1and 4f2sites. Thesteep decrease of coercivity Hc with increasing x may be caused by the Co2+preference of 4f2site and Ti4+or Zr4+ions preference of 2b and slightly in 4f1sites. The temperature coefficient of the coercivity TKHc was very low (0.01kA.m-1.°C-1)for the Co-Zr substitutions and positive for the rest of samples.