It is known, that spin glasses are disordered magnetic systems with the frustration of spins, which are freezed below the freezing temperature Tf. This states are frozen thermodynamically nonequilibrium metastable states. They have not any long-range spatial spin order and translational symmetry.Below Tf spin glass have a lot metastable states. There are free energy barriers between those states. For smaller barrier occurs more fast transition between metastable states. Aging effect is random walk in the space of the metastable states. Aging shows that spin glass system became "harder" with time. This means, that response to a field variation become more slower with aging time. In this case there is larger energy barriers. Different spin glasses have different landscape of their free energy barriers. Therefore, they have various rate of aging."Absence" aging effect, as you stated, may be caused this fact. Really aging effect occurs in the different spin glass systems, but rate of aging can strongly different. Thus, for different spin glasses it is necessary different times for observation their aging effect. I hope that this information help you.

It is known, that spin glasses are disordered magnetic systems with the frustration of spins, which are freezed below the freezing temperature Tf. This states are frozen thermodynamically nonequilibrium metastable states. They have not any long-range spatial spin order and translational symmetry.Below Tf spin glass have a lot metastable states. There are free energy barriers between those states. For smaller barrier occurs more fast transition between metastable states. Aging effect is random walk in the space of the metastable states. Aging shows that spin glass system became "harder" with time. This means, that response to a field variation become more slower with aging time. In this case there is larger energy barriers. Different spin glasses have different landscape of their free energy barriers. Therefore, they have various rate of aging."Absence" aging effect, as you stated, may be caused this fact. Really aging effect occurs in the different spin glass systems, but rate of aging can strongly different. Thus, for different spin glasses it is necessary different times for observation their aging effect. I hope that this information help you.

Thank you for replying,

So the experimental key parameter is the observation time, in order to probe the aging in each spin glass. Let me expand my question.. We say that a spin glass remembers

when we see in the rejuvenation experiments a sudden decrease in the susceptibility at the temperature where the spin glass had the "waiting" upon cooling for instance( ZFC or FC mode)..I am trying to imagine the physical picture of the configuration of the frozen spins that causes this drop of the susceptibility in this temperature that it had the waiting time..(Does this mean that the waiting induces larger energy barriers?)

I recommend you read the article added. Here you can find a lot of interesting information, including consideration of the aging process based on the droplet model.

See also next paper.

Thank you very much!the papers helped me to understand and connect my experimental findings with the droplet model.