关键词: 异常等温剩磁曲线, 逆向磁化, 菱铁矿, 热处理

Abstract: All the shapes of the isothermal remanent magnetization(IRM) curves of the samples, which were derived from the heat-treated sideriteand sand siderite samples within a certain temperature range, can be divided into three types, each corresponding one essamble of the initial states of remanent magnetization. According to the existence of segmentswith minus slope for theanomalous IRM curves, a reverse magnetic phase is suggested to have occurred during the heat treatment before and the anomalous behavior of IRM curve is tentatively explained with the coupling between a normal magnetic phase and a reverse magnetic phase. Thiskind of revere remanent magnetization were obtained by magnetizing at the room temperature and no any thermal and chemical processes participate in the magnetizing. Therefore, it differs, in essence, from the thermal and chemical reverse remanent magnetization which have been observed before.

Key words: the anomalous IRM curves, reverse magnetic, phase, heat treatment