Journal of Magnetism and Magnetic Materials 217 (2000) 93 } 98 Magnetic and dielectric properties of (CHAn)  MCl  and (An)  MCl  , where M"Cu or Mn, CHAn"4-cyclohexyl analinium and An"analinium M.G. El-Shaarawy Faculty of Science, Physics Department, Benha University, Benha, Egypt Received 29 November 1999; received in revised form 17 March 2000 Abstract The magnetic susceptibility   and the relative permittivity   for (CHAn)  MnCl  , (An)  MnCl  , (CHAn)  CuCl  and (An)  CuCl  , where CHAn"4-cyclohexyl analinium and AN"analinium ions have been studied in the temperature range of 80}400 K. The results showed antiferromagnetic character for the Mn-compounds and ferromagnetic character for Cu-compounds. The plots of   }¹ and   }¹ showed some breaks attributed to dynamic disordering of the organic chains. The results were correlated and discussed in view of the composition as well as the structure of the com- pounds.  2000 Elsevier Science B.V. All rights reserved. Keywords: Magnetic susceptibility; Dielectric constant; Two-dimensional compounds; Magnetic perovskite materials; Antiferromag- netic materials 1. Introduction The family of layered compounds with composi- tion (C  H  NH  )  MCl  , where n"1, 2, 2 and M represents of divalent transition-metal ion has received great attention due to their wide applica- tions [1}4]. The structure of such systems consists of metal-halogen layers of MX  octahedra sharing corners. Each metal-halogen layer is &sandwiched' between the non-magnetic alkyl ammonium ions (cations) to isolate it from adjacent layers. The distance between the layers depends upon the length of the cations. According to this structure the possibility to occupy the M sites by one of the E-mail address: mousa@intouch.com (M.G. El-Shaarawy). divalent transitions metals at short intra-layer dis- tance makes these substances an ideal object for studying the quasi-two-dimensional materials such as magnetic interactions [4}6]. Exchange energy between magnetic spins is a function of the distance between the ions at which the spins are located and also a function of the distortion of the electron clouds. Applying an electric "eld causes the positive non-magnetic ions to shift along the direction of the electric "eld while, on the contrary, the negative magnetic ions shift along the reverse direction. So the electron clouds around the ions are going to be distorted by an electric "eld. It will cause the e!ec- tive exchange energy between the neighboring mag- netic ions to be altered. This causes the electric "eld to modulate the strength of the exchange energy. Therefore, the dielectric constant measurements 0304-8853/00/$ - see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S 0 3 0 4 - 8 8 5 3 ( 0 0 ) 0 0 3 3 8 - 3