The accompanying diagram shows resistivity (reciprocal of conductivity) data for four solid materials from 77Kto 273K. scaled so that the maximum value plotted for each material is 1. Two are metals, one of which undergoes a transition between ordered and disordered spins in this temperature range. Speculate as to which plots correspond to these two metals and what the other two materials might be. Explain your reasoning.

The metal is a high temperature superconductor because the red curve reaches the perfect conductivity at 77K .

The current carrying capability of a material is called the electrical conductivity of that particular material.

It is an intrinsic property of the material.

It is represented by the symbol$\mathit{\sigma }$.

The reciprocal of conductivity is called resistivity. It is represented by symbol p.

The current carrying capability of a material is called the electrical conductivity of that particular material.

It is an intrinsic property of the material. It is represented by the symbol$\sigma$.

The reciprocal of conductivity is called resistivity.

It is represented by symbol p.

Consider the graph shown below.

Figure 1.

The metal is a high temperature superconductor because the red curve reaches the perfect conductivity at 77K.

The curve that goes down must be a semiconductor since its resistivity decreases with the temperature.

The pink and black curves correspond to the metals. Since, the pink is more regular so, it corresponds to the metal that gone through a transition.

Therefore, the red curve represents the superconductor, pink and black curves represent metals.

The electrical resistance should change if the microscopic order changes. In this temperature range, the light red plot appears to change, indicating that it is the one with the altered spin ordering. The other metal, whose resistance constantly decreases as temperature rises, must be the black curve. The semiconductor shown by the grey curve is most likely a semiconductor, whose resistance rises as temperature falls and the conduction band empties. The dark red conductor appears to be very typical up until a point where its resistance seems to disappear. Probably a superconductor at a high temperature.