Your calculation is algebraically equivalent to
Tickerreturns = TickerAdjClose(1:end-1,2)./TickerAdjClose(2:end,2) - 1;
Is that what you want?
Let us take the simple case of two values, which might be called Open and Close, then your calculation is (Open-Close)/Close which is Open/Close - 1 . Are you sure that is the order you want? For example alternatives would include (Close-Open)/Close and (Close-Open)/Open and (Open-Close)/Open .
Suppose something was 5 at day 1 and 10 at day 2. Then your current formula would be (5-10)/10 which would be -1/2 . Does that make sense to you? Wouldn't it make more sense to calculate (10-5)/5 = 2 ?