The powders with different content ratios of CuO[paramagnetic ] and ZnO(diamagnetic) [CuO : ZnO = 1 : 2, 1 : 1, and 2 : 1] can form. The oxides of copper can be present as diamagnetic cuprous oxide (Cu2O) or paramagnetic cupric oxide(CuO) whose stabilities depend primarily on the intensity of oxidation (annealing temperature).
The crystalline characteristics, electrical and magnetic properties depended primarily on the mixing effect and oxygenation. At low concentration of copper, the mixed oxide of Cu&Zn contain Cu2O(cuprous oxide,a diamagnetic substance) and ZnO(again a diamagnetic substance) . Diamagnetic Cu(+) ions substitute the Zn(+2) sites ( Defect structure). So at low concentrations, the mixture behaves like a diamagnetic substance.
At higher concentrations, the mixer containing copper and zinc oxides, the former being paramagnetic cupric oxide[CuO] and the latter diamagnetic zinc oxide[ZnO]i.e., the paramagneic Cu(II ) replacing diamagnetic Zn(II) in the defect structure whose cumulative effect leads to ferromagnetism which is developed by the distortion of ZnO structure by the substitution of remnant Cu2+ ions into ZnO lattice; a very well established phenomenon.
I can suggest to look at variations of the structure of your product,with high Cu content. You must check if CuO2 planes . or ladders are grown and if the Zn ions are facing these structures. In the cuprates superconductors physics it is known that the Zn ions have a deep interaction with the CuO2 planes, changing their magnetic behaviour.
G Giunchi
Thanks Manoharji how can we varify that at low concentration Cu20 and at higher concentration CuO interact.
Prepare a powder sample with known mole % of Cu. Mix well and heat at the temperature where the experiment performed. Cool at RT and determine molar magnetic susceptibility and then calculate magnetic moment. It should be be almost zero BM.
Now go on increasing the mole % of Cu while keeping the same experimental conditions and repeating the experiment a number of times till magnetic moment reaches the range1.414 -1.732BM. Note mole % of Cu.This shows the stage of the formation of CuO. Immediately before this value of mole % of Cu was the stage of the presence of Cu2O.
It will be my pleasure to send you the details of Gouy’s Magneto balance method and the formulas used to calculate molar magnetic susceptibility and the magnetic moment if required.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Material Characterization