This ordering occurs only in the solid state, and it is the kind present in the ferromagnetic elements, iron, cobalt, nickel, dysprosium, and gadolinium, and some alloys and intermetallic compounds. When individual magnetic moments interact between neighboring species, usually through other adjacent ions, their moments are antiparallel. Therefore, half the spins are in one direction and the other half in the other, so that a decrease in the magnetic susceptibility is observed, this is called antiferromagnetism. The last group to be mention is the ferromagnetic substances having a net magnetization because their moments are in one direction which causes cancellations for those in the other direction and the net magnetization results. These solids are attracted by magnets.
Temperatures effect magnetic properties of compounds.
By increase the temperature of a material, the magnetic moments move in a random patter decreasing their alignment, this is called Curie's Law. As mentioned before, the measurement of the magnetic moments of a coordination complex contains unpaired electron spins which is useful in determining the valence of the metal atom, and also in determining the structure of the complex. The Gouy method for determining magnetic susceptibility is based on the measurement of the force exerted on a sample by an in homogeneous magnetic field. When any substance is placed in a magnetic field, the field produced within the sample either a greater than or less than, the applied field, depending on whether the material is paramagnetic or diamagnetic. The way to measure the magnetic susceptibility is be using the Gouy method.