Thermomagnetic history effects in SmMn2_2Ge2_2

The intermetallic compound SmMn$_2$Ge$_2$, displaying multiple magnetic phase transitions, is being investigated in detail for its magnetization behavior near the 145 K first order ferromagnetic to antiferromagnetic transition occuring on cooling, in particular for thermomagnetic history effects in the magnetization data. The most unusual finding is that the thermomagnetic irreversibility, [= M$^{FCW}$(T)-M$^{ZFC}$(T)] at 135 K is higher in intermediate magnetic field strengths. By studying the response of the sample (i.e., thermomagnetic irreversibility and thermal hysteresis) to different histories of application of magnetic field and temperature, we demonstrate how the supercooling and superheating of the metastable magnetic phases across the first order transition at 145 K contribute to overall thermomagnetic irreversibility.Comment: 15 pages, 5 figures, to appear in Physical Review

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BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Timescale settling and nature of electron transport in magnetite - general considerations in view of new magnetic aftereffect results on dilutely Ti4+-doped Fe3O4

The effect of dil. titanium (Ti4+)-doping on the magnetic after-effect (MAE) spectra of stoichiometric magnetite single crystals, Fe3-xTixO4 - with 0.0001 ? x ? 0.008 - was studied in the temp. range 4 K TV). The recently accentuated discussion concerning the appropriate timescale of electron transport - deduced from modern x-ray resonant scattering to be about t .simeq. 10-16 s, over the whole temp. range (T [symbol omitted] TV), in contrast to up to thousands of seconds as detd. from high-precision MAE expts., in the low-temp. phase (T <TV) - gives the authors the chance to sharpen the authors' arguments in favor of a clarification of the electronic cond. mechanisms in magnetite. [on SciFinder (R)