Synthesis and thermal stability of polycrystalline new divalent [beta][double prime]- and [beta]-ferrites prepared by ion exchange

Journal Article · Mon Feb 01 04:00:00 EST 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1041· OSTI ID:6512473

Kalogirou, O ^[1]

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1. Univ. of Hamburg (Germany) Aristotle Univ., Thessaloniki (Greece)

Using ion-exchange chemistry the divalent cations Ba[sup 2+], Sr[sup 2+], Ca[sup 2+], Mg[sup 2+], Cd[sup 2+], Pb[sup 2+], Co[sup 2+], Zn[sup 2+], Mn[sup 2+], Fe[sup 2+], and Sn[sup 2+] have been substituted for K[sup +] in polycrystalline CdO-stabilized K-[beta][double prime]-ferrite samples. Ba, Sr, Ca, Mg, Pb, and Cd ion exchange led to the synthesis of new materials, the divalent M[sup 2+]-[beta][double prime]-ferrites (M = Ba, Sr, Ca, Mg) and M[sup 2+]-[beta]-ferrites (M = Cd, Pb), respectively. Co[sup 2+]-diffusion resulted in the formation of a spinel-type Co-ferrite. In the case of Zn, Mn, Fe, and Sn the samples decomposed to [alpha]-Fe[sub 2]O[sub 3]. The thermal stability of the new divalent [beta][double prime]- and [beta]-ferrites was studied either by high-temperature exchange reactions or by air annealing of the exchanged products. Ba- and Sr-[beta][double prime]-ferrites and Pb-[beta]-ferrite converted to M-type hexagonal ferrites with the magnetoplumbite structure, Mg-[beta][double prime]-ferrite decomposed to a spinel-type Mg-ferrite, and Ca-[beta][double prime]-ferrite and Cd-[beta]-ferrite decomposed to [alpha]-Fe[sub 2]O[sub 3]. Composition, lattice parameters, SEM photographs, and magnetic properties of the ferrites formed are given. The magnetic susceptibilities of the divalent [beta][double prime]- or [beta]-ferrites have values between 0.63 and 1.14 [times] 10[sup [minus]4] emu/g[center dot]Oe at room temperature. 41 refs., 1 fig., 4 tabs.

• OSTI ID: 6512473
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 102:2; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

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ALKALINE EARTH METAL COMPOUNDS
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