Correlation between spin-phonon coupling and the magnetoelectric properties of EuMnO 3 and GdMnO 3 were investigated using ceramic samples in this work. The experimental results evidence a stronger spinphonon coupling in GdMnO 3 than in EuMnO 3 , as well as a clear anomaly in the phonon contribution for the dielectric constant. This anomaly is located at the paramagnetic-incommensurate antiferromagnetic phasetransition temperature of GdMnO 3 , corroborating the existence of a magnetoelectric effect in this system. The absence of the magnetoelectric effect in EuMnO 3 is due to the existing disorder revealed in this compound by the striking thermal metastability and the large decrease in the activation energy associated with the dielectric relaxation processes. This kind of behavior has no counterpart in GdMnO 3. In fact, it has been confirmed that the existence of spin-phonon coupling is not a sufficient condition for the existence of magnetoelectric property, and other mechanisms have to be considered in order to understand the magnetoelectric properties.

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This paper presents a simple technique based on stator flux estimation to control the electromagnetic torque of the induction motor during soft starting. The inherent problems related to pure integration of the back electromagnetic force to estimate the stator flux are minimized using the low pass filter approach. The experimental results are showed and compared with usual current control technique. The obtained results validate the proposed technique showing its viability in applications where the objective is to fit the induction motor torque profile during starting or stopping according to the load torque.

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