The Influence of Quantizing Magnetic Field on the Magnetic Susceptibilities in Ultra Thin Films of Dilute Magnetic Mater
- PDF / 234,858 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 5 Downloads / 178 Views
THE INFLUENCE OF QUANTIZING MAGNETIC FIELD ON THE MAGNETIC SUSCEPTIBILITIES IN ULTRA THIN FILMS OF DILUTE MAGNETIC MATERIALS
KAMAKHYA P GHATAK* AND S. N. BISWAS** *Department of Electronics and Tele-communication Engineering, Faculty of Engineering and Technology, Jadavpur University, Calcutta 700032, INDIA. **Institut fur Halbleitertechnik, RWTH, 5100 Aachen, WSH. Sommerfeld Strasse, GERMANY. ABSTRACT
In this paper we have studied the dia and paramagnetic susceptibilities of the holes in ultrathin films of dilute magnetic materials in the presence of a quantizing magnetic field and compared the same with that of the bulk specimens under magnetic quantization for the purpose of relative comparison. It is found, taking Hg1 x Mn xTe and
CdlxMn xSe
as
examples,
that
both
the
susceptibilities
increase
with decreasing film thickness and increasing surface concentration in oscillatory manners. The numerical values of the susceptibilities in ultrathin films of dilute magnetic materials are greater than that of the bulk and the theoretical analysis is in agreement with the experimental data as reported elsewhere. Introduction The
interest in
epitaxial
films
of Cdl1xMnxTe
arises
from the novel
magnetic properties due to the Mn atoms and the close lattice match and chemical compatibility with Hg1 y CdyTe, an ideal material for long wave length infrared detectors. It is worth remarking that the close lattice match and chemical compatibility of CdMnTe with HgCdTe are important because it is possible to monolithically integrate devices such as CdTe transistors (Hg,Cd,Mn) [1,2], the heterojunction lasers [3,5] and other optical and electronic devices with HgCdTe infrared focal plane arrays. Recent advances in molecular beam epitaxy techniques have made possible the controlled substitutional doping of CdTe [6], CdMnTe [7] and CdMnTe-CdTe superlattices [8]. The combined compatibility of controlled substitutional doping and heterostructure of dilute magnetic materials make possible magnetically tuned lasers, magnetic field sensor and magnetic field sensitive transistors [9]. Though considerable work has already been done never-theless it appears from the literature that the dia and paramegnetic susceptibilities of the holes in ultrathin films of dilute magnetic materials have yet to be investigated. In this paper we shall study both the susceptibilities for the more interesting case which occurs from the presence of a quantizing magnetic field, taking Hg 1xMn xTe and CdlxMn xSe as examples. In ultrathin films the restriction of the motion of the carriers along the direction normal to the film of the layer (say, the z-direction) may be viewed as carrier confinement in a one-dimensional potential well leading to the quantization of the wave-vector of the carriers (known as quantum size effect) in the z-direction. In the presence of a quantizing magnetic field along the z-direction, the free motion parallel to the film is also quantized forming Landau levels and leading to diamagnetism. Moreover, the spinning motion
Data Loading...
