Magnetic order in the S=1/2 two-dimensional molecular antiferromagnet, copper pyrazine perchlorate Cu(Pz){sub 2}(ClO{sub 4}){sub 2}.
We present an investigation of magnetic ordering in the two-dimensional S=1/2 quantum magnet Cu(Pz){sub 2}(ClO{sub 4}){sub 2} using specific heat and zero-field muon-spin relaxation ({mu}{sup +}SR). The magnetic contribution to the specific heat is consistent with an exchange strength of 17.7(3) K. We find unambiguous evidence for a transition to a state of three-dimensional long-range order below a critical temperature T{sub N} = 4.21(1) K using {mu}{sup +} SR even though there is no feature in the specific heat at that temperature. The absence of a specific heat anomaly at T{sub N} is consistent with recent theoretical predictions. The ratio of T{sub N}/J=0.24 corresponds to a ratio of intralayer to interlayer exchange constants of |J{prime}/J| = 6.8 x 10{sup -4}, indicative of excellent two-dimensional isolation. The scaled magnetic specific heat of [Cu(Pz){sub 2}(HF{sub 2})]BF{sub 4}, a compound with an analogous structure, is very similar to that of Cu(Pz){sub 2}(ClO{sub 4}){sub 2} although both differ slightly from the predicted value for an ideal 2D S=1/2 Heisenberg antiferromagnet.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Engineering and Physical Sciences Research Council (EPSRC); Research Corp.; 1851 Commission; CNPq; CAPES; FAPERJ
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 948796
- Report Number(s):
- ANL/MSD/JA-58565; PRBMDO; TRN: US200907%%200
- Journal Information:
- Phys. Rev. B, Vol. 75, Issue 9 ; 2007; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- ENGLISH
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