A promising and original method to study the spin‐transition in bistable spin‐crossover (SCO) materials using a magnetoresistive multiring sensor and its self‐generated magnetic field is reported. Qualitative and quantitative studies are carried out combining theoretical and experimental approaches. The results show that only a small part of matter dropped on the sensor surface is probed by the device. At a low bias‐current range, the number of detected nanoparticles depends on the amplitude of the current. However, in agreement with the theoretical model, the stray voltage from the particles is proportional to the current squared. By changing both the bias current and the concentration of particle droplet, the thermal hysteresis of an ultrasmall volume, 1 × 10⁻⁴ mm³, of SCO particles is measured. The local probe of the experimental setup allows a highest resolution of 4 × 10⁻¹⁴ emu to be reached, which is never achieved by experimental methods at room temperature.

中文翻译：

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使用微磁强计研究亚皮层Sample样品的磁化率：双稳态自旋交叉材料的研究

报道了一种使用磁阻多环传感器及其自生磁场研究双稳态自旋交叉（SCO）材料中自旋转变的有前途的原始方法。定性和定量研究是结合理论和实验方法进行的。结果表明，该设备仅探测到掉落在传感器表面上的一小部分物质。在低偏置电流范围内，检测到的纳米颗粒数量取决于电流的幅度。但是，与理论模型一致，来自粒子的杂散电压与电流的平方成正比。通过同时改变偏置电流和液滴的浓度，可实现1×10 ^-4 mm ³的超小体积的热滞测量SCO颗粒的。实验装置的本地探针可实现4×10 ^-14 emu的最高分辨率，这在室温下是无法通过实验方法实现的。