Related papers: Dipolar ordering and domains in crystals of Mn$_{1…
We find that dipolar interactions favor ferromagnetic ordering of elongated crystals of Mn12 Acetate below 0.8 K. Ordered crystals must possess domain walls. Motion of the wall corresponds to a moving front of Landau-Zener transitions…
Ordering in realistic elongated box-shape crystals of the molecular magnet Mn_12 Ac is investigated with the site-resolved mean-field approximation that does not assume a uniform ordering. It is shown that ferromagnetic ordering should not…
Few examples of magnetic systems displaying a transition to pure dipolar magnetic order are known to date, and single-molecule magnets can provide an interesting example. The molecular cluster spins and thus their dipolar interaction energy…
We show that the low-temperature physics of molecular nanomagnets, contrary to the prevailing one-molecule picture, must be determined by the long-range magnetic ordering due to many-body dipolar interactions. The calculations here…
(Mn,Fe)2(P,Si) single crystals have been successfully grown by flux method. Single crystal diffraction demonstrates that Mn0.83Fe1.17P0.72Si0.28 crystallizes in a hexagonal crystal structure (space group P-62m) at both 100 and 280 K, in the…
We use neutron diffraction to probe the magnetization components of a crystal of Mn12 single-molecule magnets. Each of these molecules behaves, at low temperatures, as a nanomagnet with spin S = 10 and strong anisotropy along the…
The longitudinal magnetic susceptibility of single crystals of the molecular magnet Mn$_{12}$-acetate obeys a Curie-Weiss law, indicating a transition to a ferromagnetic phase due to dipolar interactions. With increasing magnetic field…
Single domain magnetic nanoparticles (MNP) interacting through dipolar interactions (DDI) in addition to the magnetocrystalline energy may present a low temperature ferromagnetic (SFM) or spin glass (SSG) phase according to the underlying…
Crystals of the molecular magnet Mn12-acetate are known to contain a small fraction of low- symmetry (minor) species with a small anisotropy barrier against spin reversal. The lower barrier leads to faster magnetic relaxation and lower…
The magnetic and structural phase transitions occurring in K$_2$ReCl$_6$ were studied by macroscopic and microscopic techniques. Structural phase transitions associated with rotations of the ReCl$_6$ octahedra lower the symmetry from cubic…
Precise magnetic hysteresis measurements of small single crystals of Mn$_{12}$ acetate of spin 10 have been conducted down to 0.4 K using a high sensitivity Hall magnetometer. At higher temperature (>1.6K) step-like changes in magnetization…
The magneto-optical technique has been employed to observe spontaneous ferromagnetic domain structures in La0.78Ca0.22MnO3 single crystals. The magnetic domain topology was found to be correlated with the intrinsic twin structure of the…
We report the magnetic structure of room-temperature-stable, monoclinic Mn$_3$As$_2$ at 3 K and 250 K using neutron powder diffraction measurements. From magnetometry data, the Curie temperature of Mn$_3$As$_2$ was confirmed to be around…
For studying the interplay of dipolar interaction and anisotropy energy in systems of ultrafine magnetic particles we consider simple cubic systems of magnetic dipoles with anisotropy axes pointing into the $z$-direction. Using Monte Carlo…
We report ferromagnetic ordering at $T_\mathrm {C}=1.3\,$K in the quasi-two dimensional magnet EuAl$_{12}$O$_{19}$ with large spins $S=7/2$. This ferromagnetic state was characterized by magnetization and specific heat measurements and the…
Antiferromagnetic (AF) order of U$_{2}$Pt$_{6}$Ga$_{15}$ with the ordering temperature $T_{\rm N}$ = 26 K was investigated by resonant X-ray scattering and neutron diffraction on single crystals. This compound possesses a unique crystal…
We report the first example of a transition to long-range magnetic order in a purely dipolarly interacting molecular magnet. For the magnetic cluster compound Mn6O4Br4(Et2dbm)6, the anisotropy experienced by the total spin S=12 of each…
Existence of anisotropic Curie temperature materials [E. R. Callen, Phys. Rev. 124, 1373 (1961)] is a longstanding prediction - materials that become paramagnetic along certain crystal directions at a lower temperature while remaining…
The realization of a spontaneous macroscopic ferroelectric order in fluids of anisotropic mesogens is a topic of both fundamental and technological interest. Recently, we demonstrated that a system of dipolar achiral disklike ellipsoids can…
We have grown single crystals of multiferroic double-perovskite Lu2CoMnO6 and studied the directional dependence of their magnetic and dielectric properties. The ferromagnetic order emerges below TC ~ 48K along the crystallographic c axis.…