Magnetically ordered state

A magnetic state is magnetically ordered if the atomic magnetic moments in the absence of an external magnetic field in a macroscopic crystal volume are orderly directed to each other. From this definition it is clear that a magnetically ordered state is mainly typical for a crystalline state. 

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Hence, if the crystal is initially in a magnetically ordered state at (lattice) temperature T (hot lattice + cold spins), but is then demagnetized under adiabatic conditions (q = 0), the entropy of spin disordering must be drawn from the crystal lattice (because no heat can exchange with the surroundings), and the lattice temperature drops ... 

Since the statistical averaging includes samples with different ordering orientations, this condition is fulfilled also in magnetically ordered states. 

In the model of localized magnetic moments for the spin-only state (orbital moment is quenched) the interrelation between the effective magnetic moment and the moment in the magnetically ordered state is given by... 

Mn + ions per introduced vacancy. In fact, a modest MR effect is seen for x = 0.06 and 0.11 As well, a usual charge ordering is reported for the x = 0.11 phase, which is required to explain the neutron diffraction data in the magnetically ordered state. Here layers of Mn + ions order in every fourth layer in the G-type magnetic structure known for CaMnOs (see Figure 25). ... 

The lattice dimensionality of the interacting spin system describes the number of directions in which there are extended interaction pathways. Along with the spin dimensionality, the lattice dimensionality determines if a magnetic system can spontaneously undergo a transition to a magnetically ordered state at a finite temperature (see Section 2.6). Spin and lattice dimensionalities are independent parameters so within each class of lattice dimensionality, the spins can be described by Ising-like, XY-like, or Heisenberg Hamiltonians. 

The method gives 5 g akaganeite (27% yield). The crystals are well-formed somatoids around 300 nm in length and elongated in the c-direc-tion (Fig. 9-1). The sample has a surface area of around 30 m /g and sharp XRD peaks (Fig. 9-2), indicating a well-crystallized material. An IR spectrum is shown in Fig. 9-2. The Mossbauer spectrum shows three doublets at 293 K and three sextets in the magnetically ordered state at 78 K (Fig. 9-3). 

In the magnetically ordered state, (rad)2Mn2[Cu(opba)]3(DMSO)2 2H2O presents an extremely narrow magnetic hysteresis loop. The coercive field is inferior to 10 Oe. 

By contrast, high-spin ferric complexes show only small quadrupole splittings due to the lattice terms, and in the magnetically ordered state the field is basically the Fermi term. Consequently less information is obtainable, with the notable exception of electronic relaxation times which can be deduced from the broadening which often occurs in ferric complexes. 

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