Effects of Electric field and Uniaxial Stress on Paramagnetic Spectra in Ferreoelectric Incommensurate phase and its Analyisi by Landau-Ishibashi Theoro.

用Landau-Ishibashi理论解释了A_2 BX_4型晶体的非相称相和相称相的磁共振谱的温度依赖性。考虑探针亚晶格处的局部电场和单轴应力，我们证明了分裂和共振线形状的系统温度变化，并清晰地再现了在K_2 SeO_4: SeO_4^-中报道的结果。研制了EST光谱仪用单轴应力（压力和张力）和电场施加装置。该仪器的特点是将垂直挤压器置于与施加应力垂直的静磁场中并旋转。此外，采用冷吹或热吹的方法，试样温度易于改变。利用该装置，我们观察到了铁弹性物质如LaNbo_4的不相称畴切换。我们还观察了电场和单向应力对（N(CH_3)_4）_2CoCl_4:Mn^<2+>中铁电不相称相顺磁谱的影响。

The Landau-Ishibashi theory was applied to interprete the temperature dependence of the magnetic resonance spectrum in the incommensutate and commensurate phases of A_2 BX_4 type crytals. Taking into accunt the local electric field and uniaxial stress at the probe sub-lattice, we domonstrated the systematic temperature change in the splitting and the shape of resonance lines and clearly reproduced the reported results in K_2 SeO_4 : SeO_4^-, The apparatus for applying uniaxial stress (Pressure and tension) and electric field used with EST spectrometer was developed. This appratus is characterized by perpendicular squeezer which si placed in the static magnetic fiels perpendicular to the applied stress and is rotated. Moreover the sample temperature can easily by changed by the cold ot hot gas blowing method. By using this apparatus we have observed the incommensurate domain switching of ferrroelastic substance such as LaNbo_4. We also obserbed the effect of electric field and uniazial stress on paramagnetic spectra in ferroelectric incommensurate phase in (N(CH_3)_4)_2CoCl_4 :Mn^<2+>.