Abstract

The electric field effect in electron spin resonance spectra of Fe³⁺ and Mn⁴⁺ impurity ions in thin oriented single-crystal plates of strontium titanate has been studied; the crystal structure of these samples at T > 105 K is tetragonal (i.e., differs from both cubic and antiferrodistortive tetragonal structure that is inherent in SrTiO₃ at T < 105 K). It is shown that the electric field effects for the investigated centers are quadratic with respect to the applied field and have identical signs and orders of magnitude, thus indicating a nonpolar character of the observed high-temperature tetragonal state. An analysis of the dependences of the axiality value on the applied field indicates that the electric field effect is not related to electrostriction and caused by modification of the wave function of the ground state of impurity centers.

中文翻译：

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SrTiO 3薄板中Fe 3+和Mn 4+中心的ESR光谱中的电场效应

摘要

研究了钛酸锶薄单晶板中Fe ³⁺和Mn ⁴⁺杂质离子在电子自旋共振谱中的电场效应；这些样品在T > 105 K时的晶体结构是四方的（即不同于SrTiO ₃在T处固有的立方和反铁畸变四方结构）<105 K）。结果表明，所研究中心的电场效应相对于所施加的电场是二次方的，并且具有相同的符号和数量级，因此表明所观察到的高温四方态的非极性特征。对轴向值对施加场的依赖性的分析表明，电场效应与电致伸缩无关，并且是由杂质中心基态的波函数的修改引起的。