Title
|
|
|
|
Ultralow blocking temperature and breakdown of the giant spin model in -doped nanoparticles
| |
Author
|
|
|
|
| |
Abstract
|
|
|
|
The magnetization of luminescent Er3+-doped PbF2 nanoparticles (formula Er0.3Pb0.7F2.3) has been studied. Despite the high concentration of the doping Er3+ ions and relatively large size (8 nm) of these nanoparticles we have found no deviation between field-cooled and zero-field-cooled magnetization curves down to T=0.35 K, which points out an ultralow blocking temperature for the reversal of magnetization. We also have found strongly deviating magnetization curves M(H/T) for different temperatures T. These results altogether show that the investigated nanoparticles are not superparamagnetic, but rather each Er3+ ion in these nanoparticles is found in a paramagnetic state down to very low temperatures, which implies the breakdown of the Néel-Brown giant spin model in the case of these nanoparticles. Calculations of magnetization within a paramagnetic model of noninteracting Er3+ ions completely support this conclusion. Due to the ultralow blocking temperature, these nanoparticles have a potential for magnetic field-induced nanoscale refrigeration with an option of their optical localization and temperature control. |
| |
Language
|
|
|
|
English
| |
Source (journal)
|
|
|
|
Physical review : B : condensed matter and materials physics. - Lancaster, Pa, 1998 - 2015
| |
Publication
|
|
|
|
Lancaster, Pa
:
2010
| |
ISSN
|
|
|
|
1098-0121
[print]
1550-235X
[online]
| |
Volume/pages
|
|
|
|
82
:9
(2010)
, p. 094421,1-094421,8
| |
Article Reference
|
|
|
|
094421
| |
ISI
|
|
|
|
000281773300005
| |
Medium
|
|
|
|
E-only publicatie
| |
Full text (Publisher's DOI)
|
|
|
|
| |
Full text (open access)
|
|
|
|
| |
|