Temperature Dependence of the Resonant Magnetoelectric Effect in Layered Heterostructures

The dependence of the resonant direct magnetoelectric effect on temperature is studied experimentally in planar composite structures. Samples of rectangular shapes with dimensions of 5 mm × 20 mm employed ferromagnetic layers of either an amorphous (metallic glass) alloy or nickel with a thickness of 20–200 μm and piezoelectric layers of single crystalline langatate material or lead zirconate titanate piezoelectric ceramics with a thickness of 500 μm. The temperature of the samples was varied in a range between 120 and 390 K by blowing a gaseous nitrogen stream around them. It is shown that the effective characteristics of the magnetoelectric effect—such as the mechanical resonance frequency fr, the quality factor Q and the magnitude of the magnetoelectric coefficient αE at the resonance frequency—are contingent on temperature. The interrelations between the temperature changes of the characteristics of the magnetoelectric effect and the temperature variations of the following material parameters—Young’s modulus Y, the acoustic quality factor of individual layers, the dielectric constant ε, the piezoelectric modulus d of the piezoelectric layer as well as the piezomagnetic coefficients λ(n) of the ferromagnetic layer—are established. The effect of temperature on the characteristics of the nonlinear magnetoelectric effect is observed for the first time. The results can be useful for designing magnetoelectric heterostructures with specified temperature characteristics, in particular, for the development of thermally stabilized magnetoelectric devices

Точное измерение магнитострикции в ферромагнитных пластинах

The paper describes an automated setup for measurement of magnetostrictive strain in ferromagnetic plates and films. The setup uses standard foil strain-gauges and allows the strain measurement in the range 1–2000 ppm at magnetic field up to 2 kOe. Temperature of the sample under test is stabilized with 0:05oС accuracy and can be varied from 10⁰С to 80⁰С. The sample can be rotated, settling the angle between its axis and magnetic field direction in the range 0⁰C-90⁰C. The setup was used to measure magnetostriction vs. magnetic field dependences for metglas, nickel, and permendur plates. The magnetostriction over field derivatives were calculated, which are important for study of magnetoelectric effect in composite structuresВ работе описана автоматизированная установка для измерения магнитострикции пластин и пленок ферромагнитных материалов. В основе работы установки лежит тензометрический метод с использованием стандартных пленочных тензодатчиков. Диапазон измеряемых деформаций составляет 1–2000 ppm в полях до 2 кЭ. Температура образца стабилизирована и может поддерживаться с точностью 0:05oС в диапазоне 10-80 ⁰С. Предусмотрен поворот образца в пределах 0-90 ⁰C. С помощью описанной установки были измерены полевые зависимости магнитострикции метгласа, никеля и пермендюра. Рассчитаны производные от магнитострикции по полю, необходимые для исследования магнитоэлектрического эффекта в композитных структурах

Точное измерение магнитострикции в ферромагнитных пластинах

The paper describes an automated setup for measurement of magnetostrictive strain in ferromagnetic plates and films. The setup uses standard foil strain-gauges and allows the strain measurement in the range 1–2000 ppm at magnetic field up to 2 kOe. Temperature of the sample under test is stabilized with 0:05oС accuracy and can be varied from 10⁰С to 80⁰С. The sample can be rotated, settling the angle between its axis and magnetic field direction in the range 0⁰C-90⁰C. The setup was used to measure magnetostriction vs. magnetic field dependences for metglas, nickel, and permendur plates. The magnetostriction over field derivatives were calculated, which are important for study of magnetoelectric effect in composite structuresВ работе описана автоматизированная установка для измерения магнитострикции пластин и пленок ферромагнитных материалов. В основе работы установки лежит тензометрический метод с использованием стандартных пленочных тензодатчиков. Диапазон измеряемых деформаций составляет 1–2000 ppm в полях до 2 кЭ. Температура образца стабилизирована и может поддерживаться с точностью 0:05oС в диапазоне 10-80 ⁰С. Предусмотрен поворот образца в пределах 0-90 ⁰C. С помощью описанной установки были измерены полевые зависимости магнитострикции метгласа, никеля и пермендюра. Рассчитаны производные от магнитострикции по полю, необходимые для исследования магнитоэлектрического эффекта в композитных структурах

Nuclear astrophysics with radioactive ions at FAIR

The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes