Exchange Bias in FeMn/M (M = FeNi, Gd, Tb) Films

AbstractMicrostructure and hysteretic properties of magnetic multilayers were studied for Fe50Mn50/M structures, where M = Fe19Ni81, Gd or Tb. Comparative analysis of the hysteresis loops measured for the temperature range 5÷350K showed that Gd is not involved in the interlayer exchange coupling with antiferromagnetic Fe50Mn50 layer, while in the case of Tb definite indications of such interaction were observed. It is assumed that a qualitative difference in the magnetic behavior of these rare earth layers can be caused by differences in their structural features

Ferromagnetic resonance in FeCoNi electroplated wires

[EN] We have investigated the microwave properties (ferromagnetic resonance and ferromagnetic antiresonance) of FeCoNi magnetic tubes created by electroplating on CuBe wire. Important parameters such as the g factor, magnetization, anisotropy field, and damping parameter were obtained from the measurements. One sample, prepared by a method which entails rf-sputtering deposition of an additional FeNi layer, shows a clear ferromagnetic antiresonance. (C) 2003 American Institute of Physics.This work was partially supported by Spanish Secretaria de Estado de Educación y Universidades, Generalitat Valenciana under Project No. CTIDIA/2002/50, Spanish CICyT under Grant No. MAT2000-1047, Award No. Rec-005 of the U.S. Civilian Research and Development Foundation for the Independent States of the Former Soviet Union (CRDF). One of the authors (G.V.K.) thanks Spanish MCyT for her Ramon and Cajal Fellowship. The authors thank Professor V. O. Vas kovskiy for his help.García Miquel, ÁH.; Bhagat, S.; Lofland, S.; Kurlyandskaya, G.; Svalov, A. (2003). Ferromagnetic resonance in FeCoNi electroplated wires. Journal of Applied Physics. 94(3):1868-1872. https://doi.org/10.1063/1.1590407S18681872943Sixtus, K. J., & Tonks, L. (1932). Propagation of Large Barkhausen Discontinuities. II. Physical Review, 42(3), 419-435. doi:10.1103/physrev.42.419Panina, L. V., & Mohri, K. (1994). Magneto‐impedance effect in amorphous wires. Applied Physics Letters, 65(9), 1189-1191. doi:10.1063/1.112104Vázquez, M., & Hernando, A. (1996). A soft magnetic wire for sensor applications. Journal of Physics D: Applied Physics, 29(4), 939-949. doi:10.1088/0022-3727/29/4/001Britel, M. R., Ménard, D., Melo, L. G., Ciureanu, P., Yelon, A., Cochrane, R. W., … Cornut, B. (2000). Magnetoimpedance measurements of ferromagnetic resonance and antiresonance. Applied Physics Letters, 77(17), 2737-2739. doi:10.1063/1.1320042Garcı́a-Miquel, H., Garcı́a, J. ., Garcı́a-Beneytez, J. ., & Vázquez, M. (2001). Surface magnetic anisotropy in glass-coated amorphous microwires as determined from ferromagnetic resonance measurements. Journal of Magnetism and Magnetic Materials, 231(1), 38-44. doi:10.1016/s0304-8853(01)00040-3Wiggins, J., Srikanth, H., Wang, K.-Y., Spinu, L., & Tang, J. (2000). Magneto-impedance of glass-coated Fe–Ni–Cu microwires. Journal of Applied Physics, 87(9), 4810-4812. doi:10.1063/1.373167Pirota, K. ., Kraus, L., Chiriac, H., & Knobel, M. (2000). Magnetic properties and giant magnetoimpedance in a CoFeSiB glass-covered microwire. Journal of Magnetism and Magnetic Materials, 221(3), L243-L247. doi:10.1016/s0304-8853(00)00554-0Antonov, A. S., Buznikov, N. A., Iakubov, I. T., Lagarkov, A. N., & Rakhmanov, A. L. (2001). Nonlinear magnetization reversal of Co-based amorphous microwires induced by an ac current. Journal of Physics D: Applied Physics, 34(5), 752-757. doi:10.1088/0022-3727/34/5/314Gay-Balmaz, P., Maccio, C., & Martin, O. J. F. (2002). Microwire arrays with plasmonic response at microwave frequencies. Applied Physics Letters, 81(15), 2896-2898. doi:10.1063/1.1513663Beach, R. S., Smith, N., Platt, C. L., Jeffers, F., & Berkowitz, A. E. (1996). Magneto‐impedance effect in NiFe plated wire. Applied Physics Letters, 68(19), 2753-2755. doi:10.1063/1.115587Kurlyandskaya, G. V., Barandiarán, J. M., Gutiérrez, J., Garcı́a, D., Vázquez, M., & Vas’kovskiy, V. O. (1999). Magnetoimpedance effect in CoFeNi plated wire with ac field annealing destabilized domain structure. Journal of Applied Physics, 85(8), 5438-5440. doi:10.1063/1.369968Garcia, J. ., Asenjo, A., Sinnecker, J. ., & Vazquez, M. (2000). Correlation between GMI effect and domain structure in electrodeposited Co–P tubes. Journal of Magnetism and Magnetic Materials, 215-216, 352-354. doi:10.1016/s0304-8853(00)00156-6Yu, R. H., Landry, G., Li, Y. F., Basu, S., & Xiao, J. Q. (2000). Magneto-impedance effect in soft magnetic tubes. Journal of Applied Physics, 87(9), 4807-4809. doi:10.1063/1.373166Kurlyandskaya, G. ., Garcı́a-Miquel, H., Vázquez, M., Svalov, A. ., & Vas’kovskiy, V. . (2002). Longitudinal magnetic bistability of electroplated wires. Journal of Magnetism and Magnetic Materials, 249(1-2), 34-38. doi:10.1016/s0304-8853(02)00500-0Kurlyandskaya, G. V., Yakabchuk, H., Kisker, E., Bebenin, N. G., Garcı́a-Miquel, H., Vázquez, M., & Vas’kovskiy, V. O. (2001). Very large magnetoimpedance effect in FeCoNi ferromagnetic tubes with high order magnetic anisotropy. Journal of Applied Physics, 90(12), 6280-6286. doi:10.1063/1.1418423Favieres, C., Aroca, C., Sánchez, M. C., & Madurga, V. (2000). Matteucci effect as exhibited by cylindrical CoP amorphous multilayers. Journal of Applied Physics, 87(4), 1889-1898. doi:10.1063/1.372109Lofland, S. E., Garcia-Miquel, H., Vazquez, M., & Bhagat, S. M. (2002). Microwave magnetoabsorption in glass-coated amorphous microwires with radii close to skin depth. Journal of Applied Physics, 92(4), 2058-2063. doi:10.1063/1.149484

Propiedades magnetoeléctricas de una memoria magnetorresistiva basada en películas de FeCoNi/TiN/FeCoNi

[ES] Se ha diseñado un dispositivo de memoria para la grabación y lectura de información basado en el efecto de la anisotropía magnetorresistiva de una multicapa fabricada por sputtering mediante diodo de rf. El elemento de memoria se compone de tres películas delgadas, de composición Fe15Co20Ni65(160Å)/ TiN(50Å)/Fe15Co20Ni65(160Å). El dispositivo permite procesos de grabación y lectura estables, y se compone de 32 elementos de memoria rectangulares por columna, donde cada elemento tiene dimensiones de ¿m lo que permite la fabricación de memorias integradas con capacidades del orden de 106 bits. Se han ensayado elementos de memoria rectangulares de diferentes tamaños, con las esquinas redondeadas con objeto de conseguir procesos de lectura-escritura lo más estable posible. Se han analizado comparativamente los efectos de magnetorresistencia y magnetoimpedancia de los elementos de memoria de diferentes dimensiones. Sugerimos que la disminución del valor absoluto de la magnetoimpedancia del elemento de memoria es consecuencia de la reducción de la parte real, de origen magnetorresistivo.[EN] A miniaturised memory device for information recording and readout processes have been designed on the basis of anisotropic magnetoresistive effect in Fe15Co20Ni65(160Å)/ TiN(50Å)/Fe15Co20Ni65(160Å) three-layered film done by rf diode sputtering. Stable recording and readout processes were available for 32 rectangular element column, where each element had ¿m dimensions convenient to fabricate memory chip with 106 bits capacity. Rectangles of different sizes with removed corners were used in order to define the geometry of most of all stable recording and readout processes. Magnetoresistance and magnetoimpedance effects of a magnetic memory device have been comparatively analysed. We suggest that the decrease of the absolute value of the magnetoimpedance of the memory device comes from the reduction of the real part via the magnetoresistance.Dr. G.V.Kurlyandskaya acknowledges the financial support of the Basque Government. The work has been supported by the Basque Government under the project N PI97/113 and Spanish CICYT under project MAT-98/965. We thank J. L. Muñoz for helpful discussion.Kurlyandskaya, G.; Barandiarán García, JM.; García Miquel, ÁH.; Vázquez Vilalabeitia, M.; Vaskovskiy, V.; Svalov, A. (2000). High frequency and magnetoelectrical properties of magnetoresistive memory element based on FeCoNi/TiN/FeCoNi film. Boletín de la Sociedad Española de Cerámica y Vidrio. 39(4):581-583. https://doi.org/10.3989/cyv.2000.v39.i4.824S58158339

Nanostructuring as a procedure to control the field dependence of the magnetocaloric effect

In this work, the field dependence of the magnetocaloric effect of Gd bulk samples has been enhanced through nanostructuring of the material. Nanostructuring consists in multilayers preparation by alternative rf-sputtering deposition of Gd layers and Ti spacers onto glass substrates. The results obtained for the multilayers were compared to those obtained for the Gd bulk. Assuming a power law for the field dependence of the magnetic entropy change (ΔSM ∝ Hn ), higher field dependences close to the transition in a wider temperature range are obtained for the multilayer material (n = 1.0) with respect to the bulk counterpart (n = 0.78). The effect of a Curie temperature distribution in the multilayer material (due to variations of the layer thickness) has been studied through numerical simulations to explain the observed field dependence of the magnetocaloric effect, obtaining a remarkable agreement between experiments and results.Ministerio de Economía y Competitividad español y EU-FEDER. MAT2013-45165-P y MAT2016-77265-RMinistry of Education and Science of the Russian Federation. Project No. 258

Longitudinal magnetic bistability of electroplated wires

[EN] Fe20Ni74Co6 and Fe20Ni64Co16 1 mum thick magnetic tubes electroplated onto Cu98Be2 conductive wire have been investigated in as-deposited state, after heat treatment under longitudinal magnetic field for 1 h at 330degreesC, and after rf-sputtering deposition of the additional 2 mum Fe19Ni81 layer. Heat treatments and an additional layer deposition modify the shape of hysteresis loops. Magnetically bistable behaviour, observed after the field annealing at a temperature of 330degreesC, is studied as a function of the length of the samples. This is the first report by our knowledge on the bistable behaviour of the electroplated wires. The bistability of these wires is promising for applications such as tagging or pulse generator applications. (C) 2002 Elsevier Science B.V. All rights reserved.G.V. Kurlyandskaya thanks The Basque Country University for the visiting professor invitation. We thank Prof. J.M. Barandiaran and Dr. J.L. Munoz for helpful discussion. The research has been partially supported by Award No. REC-005 of the US Civilian Research & Development Foundation for the Independent States of the Former Soviet Union (CRDF).Kurlyandskaya, G.; García Miquel, ÁH.; Vázquez, M.; Svalov, A.; Vaskovskiy, V. (2002). Longitudinal magnetic bistability of electroplated wires. Journal of Magnetism and Magnetic Materials. 249(1):34-38. https://doi.org/10.1016/S0304-8853(02)00500-0S3438249

Structure and magnetic properties of FeNi/Ti sputtered multilayers

The microstructure, anisotropic magnetoresistance, magnetic properties and magnetic domain structure of sputtered FeNi films and [Ti/FeNi]n (n = 2-16) multilayers were comparatively analyzed. It was found that although the grain size increases with an increase of the FeNi thickness both in the case of FeNi films and [Ti/FeNi]n multilayers, it did not exceed 25 nm. The values of anisotropic magnetoresistance for FeNi films and [Ti/FeNi]n multilayers were close to each other showing a weak dependence on the total thickness of the multilayered structure. Coercivity for multilayers was found to be smaller than the coercivity of single layer FeNi films. Despite the absence of a direct exchange interaction between FeNi neighboring layers in the [Ti/FeNi]n structures, their domain structures were found to be quite different from magnetic domains in single layer films due to stray field compensation in the multilayers. Obtained results are useful for the development of sensitive elements for small magnetic field detectors and planar inductors

Magnetic and resonance properties of multilayer (Gd/Si/Co/Si)ₙ films

Presented are the experimental investigation results of magnetic static and resonance properties of multilayer magnetic films in the system of 4f-3d elements separated by a semiconductor interlayer. Effects of temperature and magnetic field on interlayer coupling are detected. The role of the biquadratic exchange in formation of magnetic state in the whole system is established.Представлены результаты экспериментального исследования статических и резонансных магнитных свойств многослойных магнитных пленок в системе элементов 4f-3d, разделенных полупроводниковым промежуточным слоем. Обнаружено влияние температуры и магнитного поля на межслоевое взаимодействие. Установлена роль биквадратного обмена в формировании магнитного состояния системы как целого.Представлено результати експериментального досліджєння статичних та резонансних магнітних властивостей багатошарових магнітних плівок в системі елементів 4f-3d, розділених напівпровідниковим проміжним шаром. Виявлено вплив температури та магнітного поля на міжшарову взаємодію. Встановлено роль біквадратного обміну у формуванні магнітного стану системи як цілого