Journal of Crystal Growth 237–239 (2002) 1331–1333 Preparation of ferromagnetic quaternary (In,Ga,Mn)As T. Slupinski a, * ,1 , H. Munekata a,b , A. Oiwa a a Kanagawa Academy of Science and Technology Fund, KSP East Building 309, 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan b Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan Abstract We present preparation and magnetic properties of quaternary diluted magnetic semiconductor (In y Ga 1y ) 1x Mn x As epitaxial layers grown by molecular beam epitaxy (MBE). (In 0.53 Ga 0.47 ) 1x Mn x As grown on InP substrates shows ferromagnetic order up to 60K. Curie temperature shows linear dependence on effective Mn composition x eff ; and can be expressed in the form: T C =1300x eff : r 2002 Elsevier Science B.V. All rights reserved. PACS: 73.61.Ey; 75.50.Dd; 81.05.Ea Keywords: B2. Semiconducting III–V materials; B2. Magnetic materials According to the established knowledge of carrier-induced ferromagnetism [1], (Ga,Mn)As gives higher Curie temperature for a given Mn composition, whereas (In,Mn)As lets higher amount of Mn atoms to incorporate into the host lattice [2]. Since the magnetism in III–V diluted magnetic semiconductors depends both on the growth-related properties of metastable alloy and the strength of ferromagnetic Mn–Mn interaction, it is important to find experimentally the effect of alloying (Ga,Mn)As and (In,Mn)As on ferromag- netism, and especially on Curie temperature. Here, we report on the preparation of quaternary (In,Ga,Mn)As epitaxial layers and show the physical trends in their ferromagnetic character- istics. The quaternary layers were prepared by mole- cular beam epitaxy on three different substrates, depending on In contents, y, in (In y Ga 1y ) 1x Mn x As. A buffer layer composed of thick Ga 1y In y As (B1000nm) epitaxial film deposited on GaAs(001) substrate was used for yo0:2; whereas In 0.53 Ga 0.47 As (B100nm) layer deposited on InP(001) substrates was utilized for y ¼ 0:53 and in its vicinity. For (In,Ga,Mn)As with y > 0:9; a thick GaSb (500–750 nm) buffer layer grown on GaAs(001) substrate was used. Growth proce- dures in case of yo0:2 and > 0:9 mostly follow those used for respective ternaries (Ga,Mn)As [1] and (In,Mn)As [2,3]. Growth of In 0.53 Ga 0.47 As buffer layer on InP(0 0 1) substrate was based on well-developed procedure [4]. Growth of low temperature (LT) quaternary (In 0.53 Ga 0.47 ) 1x Mn- x As layers was based on the possibilities to grow In 0.53 Ga 0.47 As at temperatures down to 1001C demonstrated in Ref. [5]. Compositions of layers were controlled by the Ga, In and Mn arrival rates calibrated based on growth rates measurements *Corresponding author. Tel.: +81-44-819-2044; fax: +81- 44-819-2039. E-mail address: tomslu@net.ksp.or.jp (T. Slupinski). 1 On leave from Institute of Experimental Physics, Warsaw University, Poland. 0022-0248/01/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0022-0248(01)02061-9