| Автор | M Yeh |
| Автор | I S Suzuki |
| Автор | M Suzuki |
| Автор | C R Burr |
| Дата выпуска | 1990-12-10 |
| dc.description | Magnetic properties of stage 2 Co<sub>c</sub>Ni<sub>1-c</sub>Cl<sub>2</sub> graphite intercalation compounds (GICs) for 0<or=c<or=1 have been studied by DC magnetic susceptibility. These compounds can be considered to approximate two-dimensional randomly mixed ferromagnets with XY spin symmetry. As a function of Co concentration c the average effective magnetic moment P<sub>eff</sub>, and the Curie-Weiss temperature Theta have been determined. The measurements indicate that Co<sup>2+</sup> and Ni<sup>2+</sup> spins are distributed randomly on triangular lattice sites of each intercalate layer. It is found that the intraplanar exchange interaction J(Co-Ni) between the different spins is larger than that between like spins, J(Co-Co) or J(Ni-Ni):J(Co-Ni):=1.2(J(Co-Co)J(Ni-Ni))<sup>1</sup>2/. As a function of concentration, the susceptibility shows a rounding effect at the magnetic phase transition for a series of compounds with c=0.1, 0.19, 0.35, 0.40, 0.52, 0.63, 0.80 and 1.0. The authors have assumed a Gaussian distribution of transition temperatures to determine the average value of transition temperature (T<sub>c</sub>), the distribution of transition temperature sigma and the critical exponent beta . It appears that the critical exponent beta is unchanged for 0.35<or=c<or=1.0: beta =0.09+or-0.01. They obtain for the initial slope of (T<sub>c</sub>) versus c at c=0 the value -1.21+or-0.02. The ratio sigma /(T<sub>c</sub>) shows a broad peak centred at c=0.5 which is explained here qualitatively by both finite size effect and macroscopic Co concentration gradient within the intercalate layer. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Magnetic properties of stage 2 Co<sub>c</sub>Ni<sub>1-c</sub>Cl<sub>2</sub> graphite intercalation compounds |
| Тип | paper |
| DOI | 10.1088/0953-8984/2/49/009 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 2 |
| Первая страница | 9821 |
| Последняя страница | 9836 |
| Аффилиация | M Yeh; Dept. of Phys., State Univ. of New York, Binghamton, NY, USA |
| Аффилиация | I S Suzuki; Dept. of Phys., State Univ. of New York, Binghamton, NY, USA |
| Аффилиация | M Suzuki; Dept. of Phys., State Univ. of New York, Binghamton, NY, USA |
| Аффилиация | C R Burr; Dept. of Phys., State Univ. of New York, Binghamton, NY, USA |
| Выпуск | 49 |
