Properties and Device Applications of Magnetic Domains in Orthoferrites

Abstract

It has been shown that isolated magnetic domains in thin platelets (∼2 mils thick) of orthoferrites can be manipulated to perform memory, logic, and transmission functions. The purpose of this paper is to discuss the properties of orthoferrites that make them suitable for magnetic device applications and consider magnetostatic problems relevant to domain structures found to be useful. Included is a brief indication of how memory, logic, and transmission can be accomplished; however, the details will be reserved for a later paper. The stability conditions of a cylindrical domain are discussed in detail and data is reported to support the conclusions. Of particular interest are the sizes of cylindrical domains available in the various orthoferrites. Such data has been taken on five of the fourteen possible orthoferrites and it is found that the thulium orthoferrite, TmFeO3, gives the smallest stable domain diameter (2.3 mils) and LuFeO3 the largest. The stability results lead to a direct method for obtaining s̀w, the domain wall energy density. For TmFeO3, as an example, s̀w = 2.8 ergs/cm2. It is concluded that the orthoferrites are well suited indeed for device applications. Experimentally, 3 mil diameter domains have been manipulated and there is every reason to believe that operation of sub‐mil domains will soon be realized.

Magnetic properties of pulsed laser ablated YIG thin films on different substrates

“…At a substrate temperature of 800 C no sharp peak is observed and at a T s of 850 C one peak of very low intensity is observed which is very close to (8 2 0) of YIG and (2 3 1) of YFeO 3 . Saturation magnetization (4pM s ) of the films deposited in the range 600-750 C was around 100-150 G, which is close to the bulk value of YFeO 3 (100 G) [5]. On the other hand, films deposited at 850 C exhibit a 4pM s of 500 G, which is much higher than the bulk value of YFeO 3 and smaller than the bulk value of YIG.…”

The influence of growth rate on the microstructural and magnetic properties of float-zone grown crystals

“…Along with fundamental property measurements, research into possible device applications of orthoferrites has also been undertaken by many groups; in particular, in the 1960s and 1970s, the magnetic domain behavior in these materials led to a large number of investigations looking at potential applications for orthoferrites as memory or logic devices [5][6][7], as well as for pattern processing [8]. Although orthoferrites have since been overtaken by ferromagnetic garnets for magnetic bubble devices, interest in orthoferrites again took off in the 1990s, particularly from the viewpoint of their domain wall dynamics, for the velocity of the domain wall motion in orthoferrites (at up to 20 km/s) is reported to be the highest known in any magnetically ordered media [9][10][11].…”

Synthesis and physical properties of single-crystal films of rare-earth iron garnets

“…Поэтому для получения пленок с одинаковыми свойствами необходимо снижать температуру расплава по определенной программе. Результаты исследования воспроизводимости свойств для 25 пленок состава Y 3 ,eSm 0) 4Ga 1 Лучшим методом получения высококачественных пленок ферритов-гранатов с воспроизводимыми параметрами является жидкофазная эпи-таксия из раствора в расплаве. Процесс эпитаксиального роста полнее 'описывает модель, учитывающая объемную диффузию и объединение ростовых частиц в монокристалл на поверхности пленки.…”

“…Одно из направлений, с которым связывают прогресс в раз-витии средств автоматики и вычислительной техники, включает разработку устройств памяти и логики, использующих движение доменов в магнито-одноосных материалах [1][2][3][4][5][6] . Ведется также разработка магнитооптических устройств обработки и хранения информации на ферритах 4 .…”