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Polar magnets are a family of promising candidates for future magnetoelectric (ME) applications. In particular, the ME effect is recognized for its potential use in low-power electronic devices. However, searching for materials with a sufficiently strong ME effect remains the core issue. In this work, we present a systematic investigation on oxide compound Sm2BaCuO5, including the characterization on structural, magnetic, specific heat, dielectric, and pyroelectric behaviors. The intrinsic linear ME effect is revealed, and two successive antiferromagnetic phase transitions occurring at temperatures of TN1 ∼ 5 K and TN2 ∼ 23 K are found, respectively. While a magnetic field induced electric polarization emerges below TN2 and this polarization increases with the magnetic field in an almost linear manner, another weak pyroelectric current peak is detected around TN1. Furthermore, remarkable responses of both electric polarization to the magnetic field and magnetization to the electric field are demonstrated. It is suggested that the intriguing magnetic interactions play the core roles in generating the ferroelectricity and ME effect in this Sm2BaCuO5 compound.

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Searching for novel magnetoelectric (ME) materials has been one of the major issues of multiferroics. In this work, we present a systematic research study on garnet Mn 3 Al 2 Ge 3 O 12 , including structural, magnetic, heat capacity, and ME characterizations. Below the Neél temperature T N ∼ 6.8 K, Mn 2+ spins form a long-range antiferromagnetic order, and a magnetic field Hdriven electric polarization P is identified simultaneously. The relationship between P and H is nonlinear under low H and becomes linear under high H. Such transition is believed to originate from the H-induced variation of the magnetic structure. In addition, the P reaches 0.6 μC/m 2 under μ 0 H = 9 T, corresponding to an ME coupling coefficient of α ME ∼ 0.08 ps/m under high H. The small α ME is attributed to the weak spin−orbit coupling and weak magnetic interactions in Mn 3 Al 2 Ge 3 O 12 . Furthermore, we realize the stable control of P by periodically varying H, which is crucial for potential application. We provide a rare case that a garnet material shows a first-order ME effect.