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The magnetic susceptibility of the tungsten intermediary oxides WO3-x (0.05

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In 1963 Hrynkiewioz and Kulgawczuk (1 ), studying the Mtissbauer spectrum of goethite, discovered the existence of two different internal magnetic fields. The temperature dependence o f the magnitude of these fields was investigated, and it was found that one of them vanishes at about 343 OK and the other at about 373 OK. Shoe then a number of papers (2 to 7) have appeared on this subject. Their results suggest that nature produces two modifications of goethite: doublefield or A-goethite and single-field or B-goethite. crystalline (powdered) goethite (see Fig. 1) was measured using two different methods: that of Gouy and that of Sucksmith. The samples at our disposal were: a) synthetic goethite produced and supplied by W e Wolski from the Department of Inorganic Chemistry of the Poznan University, b) mineralogical goethite originating from the Polish mines Czerwona near Starachowice The RT Massbauer spectrum of both samples revealed identical Zeeman splitting, characteristic of the presence of two internal magnetic fields. The measurements by the Gouy method were carried out in the temperature range 110 to 473 OK, and the intensity of the applied magnetic field was 3.76 kOe. The measurements carried out by the Sucksmith method were performed in the region 77 to 600 OK, the applied external field was 18 kOe. For synthetic goethite both curve I and 2 show the peak of susceptibility at about 330 OK (A -point) characteristic of antiferromagnets. However, at low temperatures a marked in-The temperature dependence of the susceptibility of poly-