Powder ferrimagnetic

Synthetic ferrites also exhibit ferrimagnetism. Ferrites are magnetic ceramic materials which are made by mixing iron (III) oxide with, for instance, powdered oxides and carbonates and subsequently compressing and sintering them. They are produced in large quantities and in many different shapes. We distinguish soft and hard ferrites. 

Values obtained by powder neutron diffraction for the ferrimagnetic phase [the number of magnetic atoms (g — lgB) and non-magnetic atom is the same, see fig. 3.6. and text]. h The lower transition from antiferromagnetism to ferro/ferrimagnetism. 

The properties of these compounds are compiled in several reviews (Taylor, 1971 Wallace, 1973). They are practically all ferromagnetic (in the case of lanthanide - non-magnetic atom compounds) or ferrimagnetic (in the case of most of the lanthanide - magnetic atom compounds). Until very recently it has not been possible to grow single crystals of these materials, so practically all the neutron diffraction data have been taken on powders. Alloying with Y, La or Lu in place of the lanthanide decreases the Curie temperatures proportionally to the... 

ErN is reported by Child et al. (1963) and Wilkinson et al. (1962) to be ferrimagnetic with a similar structure as the Tb, Dy or Ho nitrides. The moments are perpendicular to the <111) direction. Powder measurements on ErN (Busch et al. 1964c) resulted in a value for the magnetization which approaches the free-ion value. A specific-heat measurement (Stutius 1969b) would yield a much too large crystal-field splitting. 

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