Low-frequency resonance of domain walls in the iron garnet Tb 3 Fe 5 O 12 near the magnetic compensation point
- PDF / 613,086 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 31 Downloads / 225 Views
DISORDER, AND PHASE TRANSITION IN CONDENSED SYSTEM
LowFrequency Resonance of Domain Walls in the Iron Garnet Tb3Fe5O12 near the Magnetic Compensation Point B. Yu. Sokolov* and M. Z. Sharipov OulougBeg National University of Uzbekistan, ul. Ulugbeka, Tashkent, 700174 Uzbekistan email: [email protected] Received August 5, 2010
Abstract—The vibrational motion dynamics of domain walls (DWs) in the iron garnet Tb3Fe5O12, a lowfre quency magnetic field, and the temperature range 200–295 K (which includes the magnetic compensation point of this ferrimagnet, Tc ≈ 249 K) is studied by a magnetooptical method. The temperature dependence of the DW vibration amplitude in this garnet crystal near Tc has a resonance character. A theoretical model of the magnetic resonance of DWs is proposed to interpret the obtained experimental results; according to this model, the DW mass tends to infinity and the resonance frequency tends to zero when temperature approaches the magnetic compensation point. DOI: 10.1134/S1063776113040109
INTRODUCTION Many rareearth iron garnets (REIGs) are known to be characterized by a magnetic compensation point, i.e., temperature Tc at which the spontaneous magnetic moments of the magnetic and RE sublattices are mutually compensated and the resulting magnetic moment of these ferromagnets Ms vanishes. When temperature passes through this point, various mag netic properties of REIGs (heat capacity, Young’s modulus, Faraday rotation, etc.) change substantially [1]. In most works dealing with this problem, researchers studied the properties of REIGs in the vicinity of Tc under magnetic saturation of a crystal (i.e., in the singledomain state of a sample) [1]. This is partly caused by the fact that, according to certain theoretical concepts, the domain structure (DS) in Tc (see, e.g., [2, 3]) REIG crystals disappears at T and, hence, does not affect their physical properties near Tc. However, using a thin singlecrystal iron gar net Tb3Fe5O12 plate as an example, we [4] showed that a stable DS is retained at T ≈ Tc in an applied magnetic field up to H ≈ 3–5 Oe. Obviously, the range of low magnetic fields is most important for the practical application of REIGs: the DS forming in these fields and the mobility of domain walls (DWs) determine the process of technical mag netization and the practically important magnetic properties of materials such as the initial susceptibility, the coercive force, and the remanent magnetization. Interest in DWs and their mobility in REIGs has recently been quickened due to the possibility of cre ating materials based on these magnetic dielectrics for the elements of nextgeneration spin electronic devices, the principle operation of which is based on
the flexomagnetoelectric effect [5]. Therefore, the purpose of this work is to study the vibrational motion of DW in an ac magnetic field in the iron garnet Tb3Fe5O12 in the vicinity of its magnetic compensation point (Tc ≈ 249 K [6]). EXPERIMENTAL The experiments were performed on the single crystal Tb3Fe5O12 sample i
Data Loading...
