3-Dy: 0.986 T; 4-Dy: 0.800 T; Figure ) compared to the SIP (0.508 T) and CIP (0.335 T). Dynamic magnetic properties were investigated for 2-Dy, 3-Dy, 4-Dy, 5-Dy, and a doped sample of 2-Dy in a diamagnetic matrix of 2-Y (5%Dy@2-Y) using AC susceptibility measurements and DC magnetization decays (2-4-Dy, 5%Dy@2-Y). Peaks in the out-of-phase AC susceptibilities (χM′′) were fitted with CC-FIT2 to the generalised Debye model to extract magnetic relaxation rates and their distributions between 44 and 86 K for 2-Dy, 36 and 93 K for 3-Dy, 46 and 97 K for 4-Dy and 2 and 73.5 K for 5-Dy. (B) and 8-53 K (C). These were fitted to the double or triple generalised Debye model using a customized script in CC-FIT2. Magnetization decays in calibrated zero field were recorded for 2-Dy (2-14 K), 3-Dy (2-20 K), 4-Dy (2-24 K) and 5%Dy@2-Y (2-16 K) and fit to the stretched exponential model to extract magnetic relaxation rates as 𝑒 -〈ln 𝜏〉 and their distributions. The temperature dependence of the magnetic relaxation rates is shown in Figure and can be fit by a combination of Orbach, Raman, QTM and phonon bottleneck process as discussed in detail below. At higher temperatures, the predominant Orbach relaxation rates follow the trend SIP ≈ CIP < 4-Dy < 3-Dy < 2-Dy << 5-Dy (Figure ); to QTM; fitting to a combination of Orbach, Raman and QTM processes (Equation S7) reveals τQTM of 10 -0.36(2) s, three orders of magnitude faster than the SIP (Table ).