Optical detection of the spin transition by reflectivity: application to

作者：W. Morscheidt, Jelena Jeftić, Épiphane Codjovi, J. Linarès, Azzedine Bousseksou, Hector Constant-Machado, F. Varret · 发表于：Measurement Science and Technology · 年份：1998 · DOI：10.1088/0957-0233/9/8/025 · 被引用次数：41 · 研究领域：Phase-change materials and chalcogenides、Liquid Crystal Research Advancements、Magneto-Optical Properties and Applications

Apparatus for measuring a reflected light signal on crystalline or powder samples of thermochromic materials, such as `spin-crossover' materials, has been developed in conjunction with a helium cryostat enabling measurements from cryogenic to ambient temperatures. Depending on the intensity and wavelength of the incident light and optical properties of the sample, reflectivity measurements provide information about a relatively thin surface layer of the investigated compound. The thermal spin transition or photoexcitation from the low-spin state, which is usually coloured, to the high-spin state, which is white or transparent, is detected by a change in the relative intensity as shown on examples of crystalline powders (btr = bis - triazole ). To compare the situation in the bulk, simultaneous magnetic measurements were performed.