This paper presents results of experiment which studied (using the Nuclear-Orientation technique) the \gamma -decay of isomeric ^180mHf. The described experiment used the newly developed mass-separated ^180mHf beam at ISOLDE, CERN which was implanted into an iron foil polarized at millikelvin temperatures. The observed irregular admixture of E2 to M2/E3 multipolarity in 501 keV 8^- \rightarrow 6⁺ \gamma -transition was the clear experimental evidence for parity mixing in nuclear states. The temperature dependence of the forward--backward asymmetry of the angular distribution has been measured over extended range of temperatures (and therefore nuclear polarizations), proving a parity mixing of the 8^- and 8⁺ nuclear levels. The value found for the E2/M2 mixing ratio \varepsilon =-0.032(2) of this transition is in close agreement with averaged value of all previously published results \varepsilon =-0.030(2).

PACS numbers: 23.40.Bw, 11.30.Er, 23.20.En, 27.70.+q