Quantum tunneling of magnetization in Mn
نویسندگان
چکیده
The Mn cluster complex [Mn 12 O 12 (CH 3 COO) 16 (H 2 O) 4 ] ) 2CH 3 COOH ) 4H 2 O exhibits macroscopic quantum tunneling of magnetic moment, as evidenced by pronounced steps in the magnetization curve at low temperatures. The magnetization of Mn 12 acetate single crystals, and the slow relaxation of the magnetic moment, was measured in the temperature range from 3 K down to 60 mK with a very sensitive cantilever magnetometer. The relaxation of the magnetic moment, at low temperatures and for magnetic fields near a step in the magnetization curve, is logarithmic and shows a complicated temperature dependence. In contrast, other investigations had found a temperature-independent relaxation, with a relaxation time saturated at 108 s. ( 1998 Elsevier Science B.V. All rights reserved.
منابع مشابه
Magnetic Deflagration and Turbulent Fronts of Quantum Detonation in Molecular Magnets1
Spin tunneling in molecular magnets such as Mn-12, boosted by a strong transverse field, should result in quantum effects in magnetic burning or deflagration. As the dipolar field can block or unblock tunneling resonances, a new possibility of propagating fronts of spin flips opens up that coexists with the standard magnetic deflagration. Here this process is being considered within a full thre...
متن کامل1 Crystal defects and spin tunneling in single crystals of Mn 12 clusters
The question addressed in this paper is that of the influence of the density of dislocations on the spin tunneling in Mn 12 clusters. We have determined the variation in the mosaicity of the crystal structure of fresh and thermally treated single crystals of Mn 12 by analyzing the widening of low angle X-ray diffraction peaks. It has also been well established from both isothermal magnetization...
متن کاملQuantum Tunneling of Magnetization in Single Domain CoFe2O4 Particles
We systematically investigated the macroscopic quantum tunneling (MQT) phenomena of magnetization in CoFe,O, particles with a diameter ranging from 30 to 92 A in zero extemal magnetic field to remove the substantial influence of energy dissipation. For all of our samples, we observed the MQT phenomena in zero external magnetic field, in spite of the anticipation that a large magnetic field H co...
متن کاملOn-chip SQUID measurements in the presence of high magnetic fields.
We report a low temperature measurement technique and the magnetization data of a quantum molecular spin, by implementing an on-chip SQUID technique. This technique enables SQUID magnetometry in high magnetic fields, up to 7 T. The main challenges and the calibration process are detailed. The measurement protocol is used to observe quantum tunneling jumps of the S = 10 molecular magnet, Mn(12)-...
متن کاملMn NMR in Mn12 acetate: Hyperfine interaction and magnetic relaxation of cluster
The 55 Mn NMR in oriented powder crystal of Mn12Ac has been investigated at 1.4−2.0 K in zero field and with external fields along the c-axis. Three kinds of 55 Mn NMR, with central frequencies at 230.2±0.1, 279.4±0.1 and 364.±0.1 MHz, composed of five-fold quadrupole-split lines for I=5/2 nuclei have been interpreted to arise from Mn 4+ ion, and two crystallographically-inequivalent Mn 3+ ions...
متن کامل